src/HOL/Multivariate_Analysis/Integration.thy
author wenzelm
Mon Oct 22 17:09:49 2012 +0200 (2012-10-22)
changeset 49970 ca5ab959c0ae
parent 49698 f68e237e8c10
child 49996 64c8d9d3af18
permissions -rw-r--r--
tuned proofs;
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header {* Kurzweil-Henstock Gauge Integration in many dimensions. *}
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(*  Author:                     John Harrison
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    Translation from HOL light: Robert Himmelmann, TU Muenchen *)
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theory Integration
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imports
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  Derivative
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  "~~/src/HOL/Library/Indicator_Function"
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begin
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declare [[smt_certificates = "Integration.certs"]]
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declare [[smt_read_only_certificates = true]]
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declare [[smt_oracle = false]]
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(*declare not_less[simp] not_le[simp]*)
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lemmas scaleR_simps = scaleR_zero_left scaleR_minus_left scaleR_left_diff_distrib
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  scaleR_zero_right scaleR_minus_right scaleR_right_diff_distrib scaleR_eq_0_iff
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  scaleR_cancel_left scaleR_cancel_right scaleR_add_right scaleR_add_left real_vector_class.scaleR_one
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lemma real_arch_invD:
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  "0 < (e::real) \<Longrightarrow> (\<exists>n::nat. n \<noteq> 0 \<and> 0 < inverse (real n) \<and> inverse (real n) < e)"
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  by (subst(asm) real_arch_inv)
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subsection {* Sundries *}
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lemma conjunctD2: assumes "a \<and> b" shows a b using assms by auto
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lemma conjunctD3: assumes "a \<and> b \<and> c" shows a b c using assms by auto
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lemma conjunctD4: assumes "a \<and> b \<and> c \<and> d" shows a b c d using assms by auto
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lemma conjunctD5: assumes "a \<and> b \<and> c \<and> d \<and> e" shows a b c d e using assms by auto
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declare norm_triangle_ineq4[intro] 
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lemma simple_image: "{f x |x . x \<in> s} = f ` s" by blast
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lemma linear_simps:
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  assumes "bounded_linear f"
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  shows
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    "f (a + b) = f a + f b"
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    "f (a - b) = f a - f b"
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    "f 0 = 0"
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    "f (- a) = - f a"
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    "f (s *\<^sub>R v) = s *\<^sub>R (f v)"
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  apply (rule_tac[!] additive.add additive.minus additive.diff additive.zero bounded_linear.scaleR)
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  using assms unfolding bounded_linear_def additive_def
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  apply auto
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  done
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lemma bounded_linearI:
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  assumes "\<And>x y. f (x + y) = f x + f y"
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    and "\<And>r x. f (r *\<^sub>R x) = r *\<^sub>R f x" "\<And>x. norm (f x) \<le> norm x * K"
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  shows "bounded_linear f"
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  unfolding bounded_linear_def additive_def bounded_linear_axioms_def using assms by auto
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lemma real_le_inf_subset:
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  assumes "t \<noteq> {}" "t \<subseteq> s" "\<exists>b. b <=* s"
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  shows "Inf s <= Inf (t::real set)"
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  apply (rule isGlb_le_isLb)
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  apply (rule Inf[OF assms(1)])
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  apply (insert assms)
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  apply (erule exE)
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  apply (rule_tac x = b in exI)
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  apply (auto simp: isLb_def setge_def)
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  done
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lemma real_ge_sup_subset:
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  assumes "t \<noteq> {}" "t \<subseteq> s" "\<exists>b. s *<= b"
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  shows "Sup s >= Sup (t::real set)"
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  apply (rule isLub_le_isUb)
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  apply (rule Sup[OF assms(1)])
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  apply (insert assms)
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  apply (erule exE)
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  apply (rule_tac x = b in exI)
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  apply (auto simp: isUb_def setle_def)
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  done
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lemma bounded_linear_component [intro]: "bounded_linear (\<lambda>x::'a::euclidean_space. x $$ k)"
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  apply (rule bounded_linearI[where K=1])
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  using component_le_norm[of _ k]
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  unfolding real_norm_def
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  apply auto
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  done
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lemma transitive_stepwise_lt_eq:
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  assumes "(\<And>x y z::nat. R x y \<Longrightarrow> R y z \<Longrightarrow> R x z)"
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  shows "((\<forall>m. \<forall>n>m. R m n) \<longleftrightarrow> (\<forall>n. R n (Suc n)))" (is "?l = ?r")
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proof (safe)
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  assume ?r
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  fix n m :: nat
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  assume "m < n"
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  then show "R m n"
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  proof (induct n arbitrary: m)
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    case (Suc n)
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    show ?case 
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    proof (cases "m < n")
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      case True
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      show ?thesis
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        apply (rule assms[OF Suc(1)[OF True]])
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        using `?r` apply auto
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        done
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    next
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      case False
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      then have "m = n" using Suc(2) by auto
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      then show ?thesis using `?r` by auto
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    qed
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  qed auto
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qed auto
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lemma transitive_stepwise_gt:
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  assumes "\<And>x y z. R x y \<Longrightarrow> R y z \<Longrightarrow> R x z" "\<And>n. R n (Suc n) "
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  shows "\<forall>n>m. R m n"
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proof -
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  have "\<forall>m. \<forall>n>m. R m n"
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    apply (subst transitive_stepwise_lt_eq)
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    apply (rule assms)
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    apply assumption
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    apply assumption
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    using assms(2) apply auto
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    done
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  then show ?thesis by auto
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qed
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lemma transitive_stepwise_le_eq:
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  assumes "\<And>x. R x x" "\<And>x y z. R x y \<Longrightarrow> R y z \<Longrightarrow> R x z"
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  shows "(\<forall>m. \<forall>n\<ge>m. R m n) \<longleftrightarrow> (\<forall>n. R n (Suc n))" (is "?l = ?r")
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proof safe
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  assume ?r
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  fix m n :: nat
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  assume "m \<le> n"
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  thus "R m n"
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  proof (induct n arbitrary: m)
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    case 0
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    with assms show ?case by auto
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  next
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    case (Suc n)
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    show ?case
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    proof (cases "m \<le> n")
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      case True
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      show ?thesis
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        apply (rule assms(2))
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        apply (rule Suc(1)[OF True])
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        using `?r` apply auto
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        done
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    next
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      case False
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      hence "m = Suc n" using Suc(2) by auto
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      thus ?thesis using assms(1) by auto
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    qed
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  qed
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qed auto
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lemma transitive_stepwise_le:
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  assumes "\<And>x. R x x" "\<And>x y z. R x y \<Longrightarrow> R y z \<Longrightarrow> R x z" "\<And>n. R n (Suc n) "
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  shows "\<forall>n\<ge>m. R m n"
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proof -
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  have "\<forall>m. \<forall>n\<ge>m. R m n"
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    apply (subst transitive_stepwise_le_eq)
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    apply (rule assms)
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    apply (rule assms,assumption,assumption)
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    using assms(3) apply auto
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    done
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  then show ?thesis by auto
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qed
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subsection {* Some useful lemmas about intervals. *}
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abbreviation One  where "One \<equiv> ((\<chi>\<chi> i. 1)::_::ordered_euclidean_space)"
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lemma empty_as_interval: "{} = {One..0}"
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  apply (rule set_eqI, rule)
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  defer
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  unfolding mem_interval
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  using UNIV_witness[where 'a='n]
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  apply (erule_tac exE, rule_tac x = x in allE)
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  apply auto
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  done
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lemma interior_subset_union_intervals: 
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  assumes "i = {a..b::'a::ordered_euclidean_space}" "j = {c..d}"
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    "interior j \<noteq> {}" "i \<subseteq> j \<union> s" "interior(i) \<inter> interior(j) = {}"
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  shows "interior i \<subseteq> interior s"
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proof -
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  have "{a<..<b} \<inter> {c..d} = {}"
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    using inter_interval_mixed_eq_empty[of c d a b] and assms(3,5)
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    unfolding assms(1,2) interior_closed_interval by auto
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  moreover
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  have "{a<..<b} \<subseteq> {c..d} \<union> s"
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    apply (rule order_trans,rule interval_open_subset_closed)
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    using assms(4) unfolding assms(1,2)
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    apply auto
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    done
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  ultimately
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  show ?thesis
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    apply -
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    apply (rule interior_maximal)
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    defer
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    apply (rule open_interior)
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    unfolding assms(1,2) interior_closed_interval
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    apply auto
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    done
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qed
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lemma inter_interior_unions_intervals:
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  fixes f::"('a::ordered_euclidean_space) set set"
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  assumes "finite f" "open s" "\<forall>t\<in>f. \<exists>a b. t = {a..b}" "\<forall>t\<in>f. s \<inter> (interior t) = {}"
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  shows "s \<inter> interior(\<Union>f) = {}"
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proof (rule ccontr, unfold ex_in_conv[THEN sym])
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  case goal1
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  have lem1: "\<And>x e s U. ball x e \<subseteq> s \<inter> interior U \<longleftrightarrow> ball x e \<subseteq> s \<inter> U"
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    apply rule
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    defer
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    apply (rule_tac Int_greatest)
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    unfolding open_subset_interior[OF open_ball]
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    using interior_subset
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    apply auto
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    done
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  have lem2: "\<And>x s P. \<exists>x\<in>s. P x \<Longrightarrow> \<exists>x\<in>insert x s. P x" by auto
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  have "\<And>f. finite f \<Longrightarrow> (\<forall>t\<in>f. \<exists>a b. t = {a..b}) \<Longrightarrow>
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    (\<exists>x. x \<in> s \<inter> interior (\<Union>f)) \<Longrightarrow> (\<exists>t\<in>f. \<exists>x. \<exists>e>0. ball x e \<subseteq> s \<inter> t)"
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  proof -
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    case goal1
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    then show ?case
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    proof (induct rule: finite_induct)
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      case empty from this(2) guess x ..
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      hence False unfolding Union_empty interior_empty by auto
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      thus ?case by auto
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    next
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      case (insert i f) guess x using insert(5) .. note x = this
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      then guess e unfolding open_contains_ball_eq[OF open_Int[OF assms(2) open_interior],rule_format] .. note e=this
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      guess a using insert(4)[rule_format,OF insertI1] ..
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      then guess b .. note ab = this
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      show ?case
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      proof (cases "x\<in>i")
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        case False
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        hence "x \<in> UNIV - {a..b}" unfolding ab by auto
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        then guess d unfolding open_contains_ball_eq[OF open_Diff[OF open_UNIV closed_interval],rule_format] ..
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        hence "0 < d" "ball x (min d e) \<subseteq> UNIV - i" unfolding ab ball_min_Int by auto
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        hence "ball x (min d e) \<subseteq> s \<inter> interior (\<Union>f)"
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          using e unfolding lem1 unfolding  ball_min_Int by auto
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        hence "x \<in> s \<inter> interior (\<Union>f)" using `d>0` e by auto
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        hence "\<exists>t\<in>f. \<exists>x e. 0 < e \<and> ball x e \<subseteq> s \<inter> t"
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          apply -
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          apply (rule insert(3))
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          using insert(4)
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          apply auto
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          done
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        thus ?thesis by auto
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      next
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        case True show ?thesis
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        proof (cases "x\<in>{a<..<b}")
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          case True
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          then guess d unfolding open_contains_ball_eq[OF open_interval,rule_format] ..
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          thus ?thesis
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            apply (rule_tac x=i in bexI, rule_tac x=x in exI, rule_tac x="min d e" in exI)
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            unfolding ab
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            using interval_open_subset_closed[of a b] and e apply fastforce+
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            done
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        next
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          case False
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          then obtain k where "x$$k \<le> a$$k \<or> x$$k \<ge> b$$k" and k:"k<DIM('a)"
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            unfolding mem_interval by (auto simp add: not_less)
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          hence "x$$k = a$$k \<or> x$$k = b$$k"
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            using True unfolding ab and mem_interval
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              apply (erule_tac x = k in allE)
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              apply auto
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              done
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          hence "\<exists>x. ball x (e/2) \<subseteq> s \<inter> (\<Union>f)"
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          proof (erule_tac disjE)
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            let ?z = "x - (e/2) *\<^sub>R basis k"
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            assume as: "x$$k = a$$k"
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            have "ball ?z (e / 2) \<inter> i = {}"
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              apply (rule ccontr)
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              unfolding ex_in_conv[THEN sym]
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            proof (erule exE)
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              fix y
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              assume "y \<in> ball ?z (e / 2) \<inter> i"
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              hence "dist ?z y < e/2" and yi:"y\<in>i" by auto
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              hence "\<bar>(?z - y) $$ k\<bar> < e/2"
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                using component_le_norm[of "?z - y" k] unfolding dist_norm by auto
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              hence "y$$k < a$$k"
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                using e[THEN conjunct1] k by (auto simp add: field_simps as)
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              hence "y \<notin> i"
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                unfolding ab mem_interval not_all
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                apply (rule_tac x=k in exI)
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                using k apply auto
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                done
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              thus False using yi by auto
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            qed
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            moreover
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            have "ball ?z (e/2) \<subseteq> s \<inter> (\<Union>insert i f)"
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              apply(rule order_trans[OF _ e[THEN conjunct2, unfolded lem1]])
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            proof
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              fix y
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              assume as: "y\<in> ball ?z (e/2)"
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              have "norm (x - y) \<le> \<bar>e\<bar> / 2 + norm (x - y - (e / 2) *\<^sub>R basis k)"
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                apply -
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                apply (rule order_trans,rule norm_triangle_sub[of "x - y" "(e/2) *\<^sub>R basis k"])
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                unfolding norm_scaleR norm_basis
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                apply auto
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                done
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              also have "\<dots> < \<bar>e\<bar> / 2 + \<bar>e\<bar> / 2"
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                apply (rule add_strict_left_mono)
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                using as unfolding mem_ball dist_norm
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                using e apply (auto simp add: field_simps)
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                done
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              finally show "y\<in>ball x e"
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                unfolding mem_ball dist_norm using e by (auto simp add:field_simps)
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   310
            qed
wenzelm@49970
   311
            ultimately show ?thesis
wenzelm@49970
   312
              apply (rule_tac x="?z" in exI)
wenzelm@49970
   313
              unfolding Union_insert
wenzelm@49970
   314
              apply auto
wenzelm@49970
   315
              done
wenzelm@49970
   316
          next
wenzelm@49970
   317
            let ?z = "x + (e/2) *\<^sub>R basis k"
wenzelm@49970
   318
            assume as: "x$$k = b$$k"
wenzelm@49970
   319
            have "ball ?z (e / 2) \<inter> i = {}"
wenzelm@49970
   320
              apply (rule ccontr)
wenzelm@49970
   321
              unfolding ex_in_conv[THEN sym]
wenzelm@49970
   322
            proof(erule exE)
wenzelm@49970
   323
              fix y
wenzelm@49970
   324
              assume "y \<in> ball ?z (e / 2) \<inter> i"
wenzelm@49970
   325
              hence "dist ?z y < e/2" and yi:"y\<in>i" by auto
wenzelm@49970
   326
              hence "\<bar>(?z - y) $$ k\<bar> < e/2"
wenzelm@49970
   327
                using component_le_norm[of "?z - y" k] unfolding dist_norm by auto
wenzelm@49970
   328
              hence "y$$k > b$$k"
wenzelm@49970
   329
                using e[THEN conjunct1] k by(auto simp add:field_simps as)
wenzelm@49970
   330
              hence "y \<notin> i"
wenzelm@49970
   331
                unfolding ab mem_interval not_all
wenzelm@49970
   332
                using k apply (rule_tac x=k in exI)
wenzelm@49970
   333
                apply auto
wenzelm@49970
   334
                done
wenzelm@49970
   335
              thus False using yi by auto
wenzelm@49970
   336
            qed
wenzelm@49970
   337
            moreover
wenzelm@49970
   338
            have "ball ?z (e/2) \<subseteq> s \<inter> (\<Union>insert i f)"
wenzelm@49970
   339
              apply (rule order_trans[OF _ e[THEN conjunct2, unfolded lem1]])
wenzelm@49970
   340
            proof
wenzelm@49970
   341
              fix y
wenzelm@49970
   342
              assume as: "y\<in> ball ?z (e/2)"
wenzelm@49970
   343
              have "norm (x - y) \<le> \<bar>e\<bar> / 2 + norm (x - y + (e / 2) *\<^sub>R basis k)"
wenzelm@49970
   344
                apply -
wenzelm@49970
   345
                apply(rule order_trans,rule norm_triangle_sub[of "x - y" "- (e/2) *\<^sub>R basis k"])
wenzelm@49970
   346
                unfolding norm_scaleR
wenzelm@49970
   347
                apply auto
wenzelm@49970
   348
                done
wenzelm@49970
   349
              also have "\<dots> < \<bar>e\<bar> / 2 + \<bar>e\<bar> / 2"
wenzelm@49970
   350
                apply (rule add_strict_left_mono)
wenzelm@49970
   351
                using as unfolding mem_ball dist_norm
wenzelm@49970
   352
                using e apply (auto simp add: field_simps)
wenzelm@49970
   353
                done
wenzelm@49970
   354
              finally show "y\<in>ball x e"
wenzelm@49970
   355
                unfolding mem_ball dist_norm using e by(auto simp add:field_simps)
wenzelm@49970
   356
            qed
wenzelm@49970
   357
            ultimately show ?thesis
wenzelm@49970
   358
              apply (rule_tac x="?z" in exI)
wenzelm@49970
   359
              unfolding Union_insert
wenzelm@49970
   360
              apply auto
wenzelm@49970
   361
              done
wenzelm@49970
   362
          qed 
wenzelm@49970
   363
          then guess x ..
wenzelm@49970
   364
          hence "x \<in> s \<inter> interior (\<Union>f)"
wenzelm@49970
   365
            unfolding lem1[where U="\<Union>f",THEN sym]
wenzelm@49970
   366
            using centre_in_ball e[THEN conjunct1] by auto
wenzelm@49970
   367
          thus ?thesis
wenzelm@49970
   368
            apply -
wenzelm@49970
   369
            apply (rule lem2, rule insert(3))
wenzelm@49970
   370
            using insert(4) apply auto
wenzelm@49970
   371
            done
wenzelm@49970
   372
        qed
wenzelm@49970
   373
      qed
wenzelm@49970
   374
    qed
wenzelm@49970
   375
  qed
wenzelm@49970
   376
  note * = this
wenzelm@49970
   377
  guess t using *[OF assms(1,3) goal1] ..
wenzelm@49970
   378
  from this(2) guess x ..
wenzelm@49970
   379
  then guess e ..
wenzelm@49970
   380
  hence "x \<in> s" "x\<in>interior t"
wenzelm@49970
   381
    defer
wenzelm@49970
   382
    using open_subset_interior[OF open_ball, of x e t] apply auto
wenzelm@49970
   383
    done
wenzelm@49970
   384
  thus False using `t\<in>f` assms(4) by auto
wenzelm@49970
   385
qed
wenzelm@49970
   386
hoelzl@37489
   387
himmelma@35172
   388
subsection {* Bounds on intervals where they exist. *}
himmelma@35172
   389
wenzelm@49970
   390
definition "interval_upperbound (s::('a::ordered_euclidean_space) set) =
wenzelm@49970
   391
  ((\<chi>\<chi> i. Sup {a. \<exists>x\<in>s. x$$i = a})::'a)"
wenzelm@49970
   392
wenzelm@49970
   393
definition "interval_lowerbound (s::('a::ordered_euclidean_space) set) =
wenzelm@49970
   394
  ((\<chi>\<chi> i. Inf {a. \<exists>x\<in>s. x$$i = a})::'a)"
wenzelm@49970
   395
wenzelm@49970
   396
lemma interval_upperbound[simp]:
wenzelm@49970
   397
  assumes "\<forall>i<DIM('a::ordered_euclidean_space). a$$i \<le> (b::'a)$$i"
wenzelm@49970
   398
  shows "interval_upperbound {a..b} = b"
wenzelm@49970
   399
  using assms
wenzelm@49970
   400
  unfolding interval_upperbound_def
wenzelm@49970
   401
  apply (subst euclidean_eq[where 'a='a])
wenzelm@49970
   402
  apply safe
wenzelm@49970
   403
  unfolding euclidean_lambda_beta'
wenzelm@49970
   404
  apply (erule_tac x=i in allE)
wenzelm@49970
   405
  apply (rule Sup_unique)
wenzelm@49970
   406
  unfolding setle_def
wenzelm@49970
   407
  apply rule
wenzelm@49970
   408
  unfolding mem_Collect_eq
wenzelm@49970
   409
  apply (erule bexE)
wenzelm@49970
   410
  unfolding mem_interval
wenzelm@49970
   411
  defer
wenzelm@49970
   412
  apply (rule, rule)
wenzelm@49970
   413
  apply (rule_tac x="b$$i" in bexI)
wenzelm@49970
   414
  defer
wenzelm@49970
   415
  unfolding mem_Collect_eq
wenzelm@49970
   416
  apply (rule_tac x=b in bexI)
wenzelm@49970
   417
  unfolding mem_interval
wenzelm@49970
   418
  using assms apply auto
wenzelm@49970
   419
  done
wenzelm@49970
   420
wenzelm@49970
   421
lemma interval_lowerbound[simp]:
wenzelm@49970
   422
  assumes "\<forall>i<DIM('a::ordered_euclidean_space). a$$i \<le> (b::'a)$$i"
wenzelm@49970
   423
  shows "interval_lowerbound {a..b} = a"
wenzelm@49970
   424
  using assms
wenzelm@49970
   425
  unfolding interval_lowerbound_def
wenzelm@49970
   426
  apply (subst euclidean_eq[where 'a='a])
wenzelm@49970
   427
  apply safe
wenzelm@49970
   428
  unfolding euclidean_lambda_beta'
wenzelm@49970
   429
  apply (erule_tac x=i in allE)
wenzelm@49970
   430
  apply (rule Inf_unique)
wenzelm@49970
   431
  unfolding setge_def
wenzelm@49970
   432
  apply rule
wenzelm@49970
   433
  unfolding mem_Collect_eq
wenzelm@49970
   434
  apply (erule bexE)
wenzelm@49970
   435
  unfolding mem_interval
wenzelm@49970
   436
  defer
wenzelm@49970
   437
  apply (rule, rule)
wenzelm@49970
   438
  apply (rule_tac x = "a$$i" in bexI)
wenzelm@49970
   439
  defer
wenzelm@49970
   440
  unfolding mem_Collect_eq
wenzelm@49970
   441
  apply (rule_tac x=a in bexI)
wenzelm@49970
   442
  unfolding mem_interval
wenzelm@49970
   443
  using assms apply auto
wenzelm@49970
   444
  done
himmelma@35172
   445
himmelma@35172
   446
lemmas interval_bounds = interval_upperbound interval_lowerbound
himmelma@35172
   447
wenzelm@49970
   448
lemma interval_bounds'[simp]:
wenzelm@49970
   449
  assumes "{a..b}\<noteq>{}"
wenzelm@49970
   450
  shows "interval_upperbound {a..b} = b" "interval_lowerbound {a..b} = a"
himmelma@35172
   451
  using assms unfolding interval_ne_empty by auto
himmelma@35172
   452
himmelma@35172
   453
subsection {* Content (length, area, volume...) of an interval. *}
himmelma@35172
   454
hoelzl@37489
   455
definition "content (s::('a::ordered_euclidean_space) set) =
wenzelm@49970
   456
  (if s = {} then 0 else (\<Prod>i<DIM('a). (interval_upperbound s)$$i - (interval_lowerbound s)$$i))"
hoelzl@37489
   457
hoelzl@37489
   458
lemma interval_not_empty:"\<forall>i<DIM('a). a$$i \<le> b$$i \<Longrightarrow> {a..b::'a::ordered_euclidean_space} \<noteq> {}"
hoelzl@37489
   459
  unfolding interval_eq_empty unfolding not_ex not_less by auto
hoelzl@37489
   460
wenzelm@49970
   461
lemma content_closed_interval:
wenzelm@49970
   462
  fixes a::"'a::ordered_euclidean_space"
wenzelm@49970
   463
  assumes "\<forall>i<DIM('a). a$$i \<le> b$$i"
wenzelm@49970
   464
  shows "content {a..b} = (\<Prod>i<DIM('a). b$$i - a$$i)"
wenzelm@49970
   465
  using interval_not_empty[OF assms]
wenzelm@49970
   466
  unfolding content_def interval_upperbound[OF assms] interval_lowerbound[OF assms]
wenzelm@49970
   467
  by auto
wenzelm@49970
   468
wenzelm@49970
   469
lemma content_closed_interval':
wenzelm@49970
   470
  fixes a::"'a::ordered_euclidean_space"
wenzelm@49970
   471
  assumes "{a..b}\<noteq>{}"
hoelzl@37489
   472
  shows "content {a..b} = (\<Prod>i<DIM('a). b$$i - a$$i)"
wenzelm@49970
   473
  apply (rule content_closed_interval)
wenzelm@49970
   474
  using assms unfolding interval_ne_empty
wenzelm@49970
   475
  apply assumption
wenzelm@49970
   476
  done
wenzelm@49970
   477
wenzelm@49970
   478
lemma content_real:
wenzelm@49970
   479
  assumes "a\<le>b"
wenzelm@49970
   480
  shows "content {a..b} = b-a"
wenzelm@49970
   481
proof -
wenzelm@49970
   482
  have *: "{..<Suc 0} = {0}" by auto
wenzelm@49970
   483
  show ?thesis unfolding content_def using assms by (auto simp: *)
hoelzl@37489
   484
qed
hoelzl@37489
   485
wenzelm@49970
   486
lemma content_unit[intro]: "content{0..One::'a::ordered_euclidean_space} = 1"
wenzelm@49970
   487
proof -
wenzelm@49970
   488
  have *: "\<forall>i<DIM('a). (0::'a)$$i \<le> (One::'a)$$i" by auto
hoelzl@37489
   489
  have "0 \<in> {0..One::'a}" unfolding mem_interval by auto
wenzelm@49970
   490
  thus ?thesis unfolding content_def interval_bounds[OF *] using setprod_1 by auto
wenzelm@49970
   491
qed
wenzelm@49970
   492
wenzelm@49970
   493
lemma content_pos_le[intro]:
wenzelm@49970
   494
  fixes a::"'a::ordered_euclidean_space"
wenzelm@49970
   495
  shows "0 \<le> content {a..b}"
wenzelm@49970
   496
proof (cases "{a..b} = {}")
wenzelm@49970
   497
  case False
wenzelm@49970
   498
  hence *: "\<forall>i<DIM('a). a $$ i \<le> b $$ i" unfolding interval_ne_empty .
hoelzl@37489
   499
  have "(\<Prod>i<DIM('a). interval_upperbound {a..b} $$ i - interval_lowerbound {a..b} $$ i) \<ge> 0"
wenzelm@49970
   500
    apply (rule setprod_nonneg)
wenzelm@49970
   501
    unfolding interval_bounds[OF *]
wenzelm@49970
   502
    using *
wenzelm@49970
   503
    apply (erule_tac x=x in allE)
wenzelm@49970
   504
    apply auto
wenzelm@49970
   505
    done
wenzelm@49970
   506
  thus ?thesis unfolding content_def by (auto simp del:interval_bounds')
wenzelm@49970
   507
qed (unfold content_def, auto)
wenzelm@49970
   508
wenzelm@49970
   509
lemma content_pos_lt:
wenzelm@49970
   510
  fixes a::"'a::ordered_euclidean_space"
wenzelm@49970
   511
  assumes "\<forall>i<DIM('a). a$$i < b$$i"
wenzelm@49970
   512
  shows "0 < content {a..b}"
wenzelm@49970
   513
proof -
wenzelm@49970
   514
  have help_lemma1: "\<forall>i<DIM('a). a$$i < b$$i \<Longrightarrow> \<forall>i<DIM('a). a$$i \<le> ((b$$i)::real)"
wenzelm@49970
   515
    apply (rule, erule_tac x=i in allE)
wenzelm@49970
   516
    apply auto
wenzelm@49970
   517
    done
wenzelm@49970
   518
  show ?thesis unfolding content_closed_interval[OF help_lemma1[OF assms]]
wenzelm@49970
   519
    apply(rule setprod_pos)
wenzelm@49970
   520
    using assms apply (erule_tac x=x in allE)
wenzelm@49970
   521
    apply auto
wenzelm@49970
   522
    done
wenzelm@49970
   523
qed
wenzelm@49970
   524
wenzelm@49970
   525
lemma content_eq_0: "content{a..b::'a::ordered_euclidean_space} = 0 \<longleftrightarrow> (\<exists>i<DIM('a). b$$i \<le> a$$i)"
wenzelm@49970
   526
proof (cases "{a..b} = {}")
wenzelm@49970
   527
  case True
wenzelm@49970
   528
  thus ?thesis
wenzelm@49970
   529
    unfolding content_def if_P[OF True]
wenzelm@49970
   530
    unfolding interval_eq_empty
wenzelm@49970
   531
    apply -
wenzelm@49970
   532
    apply (rule, erule exE)
wenzelm@49970
   533
    apply (rule_tac x = i in exI)
wenzelm@49970
   534
    apply auto
wenzelm@49970
   535
    done
wenzelm@49970
   536
next
wenzelm@49970
   537
  case False
wenzelm@49970
   538
  from this[unfolded interval_eq_empty not_ex not_less]
wenzelm@49970
   539
  have as: "\<forall>i<DIM('a). b $$ i \<ge> a $$ i" by fastforce
wenzelm@49970
   540
  show ?thesis
wenzelm@49970
   541
    unfolding content_def if_not_P[OF False] setprod_zero_iff[OF finite_lessThan]
wenzelm@49970
   542
    apply rule
wenzelm@49970
   543
    apply (erule_tac[!] exE bexE)
wenzelm@49970
   544
    unfolding interval_bounds[OF as]
wenzelm@49970
   545
    apply (rule_tac x=x in exI)
wenzelm@49970
   546
    defer
wenzelm@49970
   547
    apply (rule_tac x=i in bexI)
wenzelm@49970
   548
    using as apply (erule_tac x=i in allE)
wenzelm@49970
   549
    apply auto
wenzelm@49970
   550
    done
wenzelm@49970
   551
qed
himmelma@35172
   552
himmelma@35172
   553
lemma cond_cases:"(P \<Longrightarrow> Q x) \<Longrightarrow> (\<not> P \<Longrightarrow> Q y) \<Longrightarrow> Q (if P then x else y)" by auto
himmelma@35172
   554
himmelma@35172
   555
lemma content_closed_interval_cases:
wenzelm@49970
   556
  "content {a..b::'a::ordered_euclidean_space} =
wenzelm@49970
   557
    (if \<forall>i<DIM('a). a$$i \<le> b$$i then setprod (\<lambda>i. b$$i - a$$i) {..<DIM('a)} else 0)"
wenzelm@49970
   558
  apply (rule cond_cases) 
wenzelm@49970
   559
  apply (rule content_closed_interval)
wenzelm@49970
   560
  unfolding content_eq_0 not_all not_le
wenzelm@49970
   561
  defer
wenzelm@49970
   562
  apply (erule exE,rule_tac x=x in exI)
wenzelm@49970
   563
  apply auto
wenzelm@49970
   564
  done
himmelma@35172
   565
himmelma@35172
   566
lemma content_eq_0_interior: "content {a..b} = 0 \<longleftrightarrow> interior({a..b}) = {}"
himmelma@35172
   567
  unfolding content_eq_0 interior_closed_interval interval_eq_empty by auto
himmelma@35172
   568
hoelzl@37489
   569
(*lemma content_eq_0_1: "content {a..b::real^1} = 0 \<longleftrightarrow> dest_vec1 b \<le> dest_vec1 a"
hoelzl@37489
   570
  unfolding content_eq_0 by auto*)
hoelzl@37489
   571
hoelzl@37489
   572
lemma content_pos_lt_eq: "0 < content {a..b::'a::ordered_euclidean_space} \<longleftrightarrow> (\<forall>i<DIM('a). a$$i < b$$i)"
wenzelm@49970
   573
  apply rule
wenzelm@49970
   574
  defer
wenzelm@49970
   575
  apply (rule content_pos_lt, assumption)
wenzelm@49970
   576
proof -
wenzelm@49970
   577
  assume "0 < content {a..b}"
wenzelm@49970
   578
  hence "content {a..b} \<noteq> 0" by auto
wenzelm@49970
   579
  thus "\<forall>i<DIM('a). a$$i < b$$i"
wenzelm@49970
   580
    unfolding content_eq_0 not_ex not_le by fastforce
wenzelm@49970
   581
qed
wenzelm@49970
   582
wenzelm@49970
   583
lemma content_empty [simp]: "content {} = 0" unfolding content_def by auto
himmelma@35172
   584
wenzelm@49698
   585
lemma content_subset:
wenzelm@49698
   586
  assumes "{a..b} \<subseteq> {c..d}"
wenzelm@49698
   587
  shows "content {a..b::'a::ordered_euclidean_space} \<le> content {c..d}"
wenzelm@49698
   588
proof (cases "{a..b} = {}")
wenzelm@49698
   589
  case True
wenzelm@49698
   590
  thus ?thesis using content_pos_le[of c d] by auto
wenzelm@49698
   591
next
wenzelm@49698
   592
  case False
wenzelm@49698
   593
  hence ab_ne:"\<forall>i<DIM('a). a $$ i \<le> b $$ i" unfolding interval_ne_empty by auto
himmelma@35172
   594
  hence ab_ab:"a\<in>{a..b}" "b\<in>{a..b}" unfolding mem_interval by auto
himmelma@35172
   595
  have "{c..d} \<noteq> {}" using assms False by auto
hoelzl@37489
   596
  hence cd_ne:"\<forall>i<DIM('a). c $$ i \<le> d $$ i" using assms unfolding interval_ne_empty by auto
wenzelm@49698
   597
  show ?thesis
wenzelm@49698
   598
    unfolding content_def
wenzelm@49698
   599
    unfolding interval_bounds[OF ab_ne] interval_bounds[OF cd_ne]
wenzelm@49698
   600
    unfolding if_not_P[OF False] if_not_P[OF `{c..d} \<noteq> {}`]
wenzelm@49698
   601
    apply(rule setprod_mono,rule)
wenzelm@49698
   602
  proof
wenzelm@49698
   603
    fix i
wenzelm@49698
   604
    assume i:"i\<in>{..<DIM('a)}"
hoelzl@37489
   605
    show "0 \<le> b $$ i - a $$ i" using ab_ne[THEN spec[where x=i]] i by auto
hoelzl@37489
   606
    show "b $$ i - a $$ i \<le> d $$ i - c $$ i"
himmelma@35172
   607
      using assms[unfolded subset_eq mem_interval,rule_format,OF ab_ab(2),of i]
wenzelm@49698
   608
      using assms[unfolded subset_eq mem_interval,rule_format,OF ab_ab(1),of i]
wenzelm@49698
   609
      using i by auto
wenzelm@49698
   610
  qed
wenzelm@49698
   611
qed
himmelma@35172
   612
himmelma@35172
   613
lemma content_lt_nz: "0 < content {a..b} \<longleftrightarrow> content {a..b} \<noteq> 0"
nipkow@44890
   614
  unfolding content_pos_lt_eq content_eq_0 unfolding not_ex not_le by fastforce
himmelma@35172
   615
wenzelm@49698
   616
himmelma@35172
   617
subsection {* The notion of a gauge --- simply an open set containing the point. *}
himmelma@35172
   618
himmelma@35172
   619
definition gauge where "gauge d \<longleftrightarrow> (\<forall>x. x\<in>(d x) \<and> open(d x))"
himmelma@35172
   620
wenzelm@49698
   621
lemma gaugeI: assumes "\<And>x. x\<in>g x" "\<And>x. open (g x)" shows "gauge g"
himmelma@35172
   622
  using assms unfolding gauge_def by auto
himmelma@35172
   623
wenzelm@49698
   624
lemma gaugeD[dest]: assumes "gauge d" shows "x\<in>d x" "open (d x)"
wenzelm@49698
   625
  using assms unfolding gauge_def by auto
himmelma@35172
   626
himmelma@35172
   627
lemma gauge_ball_dependent: "\<forall>x. 0 < e x \<Longrightarrow> gauge (\<lambda>x. ball x (e x))"
himmelma@35172
   628
  unfolding gauge_def by auto 
himmelma@35172
   629
himmelma@35751
   630
lemma gauge_ball[intro]: "0 < e \<Longrightarrow> gauge (\<lambda>x. ball x e)" unfolding gauge_def by auto 
himmelma@35172
   631
wenzelm@49698
   632
lemma gauge_trivial[intro]: "gauge (\<lambda>x. ball x 1)"
wenzelm@49698
   633
  by (rule gauge_ball) auto
himmelma@35172
   634
himmelma@35751
   635
lemma gauge_inter[intro]: "gauge d1 \<Longrightarrow> gauge d2 \<Longrightarrow> gauge (\<lambda>x. (d1 x) \<inter> (d2 x))"
himmelma@35172
   636
  unfolding gauge_def by auto 
himmelma@35172
   637
wenzelm@49698
   638
lemma gauge_inters:
wenzelm@49698
   639
  assumes "finite s" "\<forall>d\<in>s. gauge (f d)"
wenzelm@49698
   640
  shows "gauge(\<lambda>x. \<Inter> {f d x | d. d \<in> s})"
wenzelm@49698
   641
proof -
wenzelm@49698
   642
  have *:"\<And>x. {f d x |d. d \<in> s} = (\<lambda>d. f d x) ` s" by auto
wenzelm@49698
   643
  show ?thesis
wenzelm@49698
   644
    unfolding gauge_def unfolding * 
wenzelm@49698
   645
    using assms unfolding Ball_def Inter_iff mem_Collect_eq gauge_def by auto
wenzelm@49698
   646
qed
wenzelm@49698
   647
wenzelm@49698
   648
lemma gauge_existence_lemma: "(\<forall>x. \<exists>d::real. p x \<longrightarrow> 0 < d \<and> q d x) \<longleftrightarrow> (\<forall>x. \<exists>d>0. p x \<longrightarrow> q d x)"
wenzelm@49698
   649
  by(meson zero_less_one)
wenzelm@49698
   650
himmelma@35172
   651
himmelma@35172
   652
subsection {* Divisions. *}
himmelma@35172
   653
himmelma@35172
   654
definition division_of (infixl "division'_of" 40) where
himmelma@35172
   655
  "s division_of i \<equiv>
himmelma@35172
   656
        finite s \<and>
himmelma@35172
   657
        (\<forall>k\<in>s. k \<subseteq> i \<and> k \<noteq> {} \<and> (\<exists>a b. k = {a..b})) \<and>
himmelma@35172
   658
        (\<forall>k1\<in>s. \<forall>k2\<in>s. k1 \<noteq> k2 \<longrightarrow> interior(k1) \<inter> interior(k2) = {}) \<and>
himmelma@35172
   659
        (\<Union>s = i)"
himmelma@35172
   660
wenzelm@49698
   661
lemma division_ofD[dest]:
wenzelm@49698
   662
  assumes "s division_of i"
wenzelm@49698
   663
  shows "finite s" "\<And>k. k\<in>s \<Longrightarrow> k \<subseteq> i" "\<And>k. k\<in>s \<Longrightarrow>  k \<noteq> {}" "\<And>k. k\<in>s \<Longrightarrow> (\<exists>a b. k = {a..b})"
wenzelm@49698
   664
    "\<And>k1 k2. \<lbrakk>k1\<in>s; k2\<in>s; k1 \<noteq> k2\<rbrakk> \<Longrightarrow> interior(k1) \<inter> interior(k2) = {}" "\<Union>s = i"
wenzelm@49698
   665
  using assms unfolding division_of_def by auto
himmelma@35172
   666
himmelma@35172
   667
lemma division_ofI:
himmelma@35172
   668
  assumes "finite s" "\<And>k. k\<in>s \<Longrightarrow> k \<subseteq> i" "\<And>k. k\<in>s \<Longrightarrow>  k \<noteq> {}" "\<And>k. k\<in>s \<Longrightarrow> (\<exists>a b. k = {a..b})"
wenzelm@49698
   669
    "\<And>k1 k2. \<lbrakk>k1\<in>s; k2\<in>s; k1 \<noteq> k2\<rbrakk> \<Longrightarrow> interior(k1) \<inter> interior(k2) = {}" "\<Union>s = i"
himmelma@35172
   670
  shows "s division_of i" using assms unfolding division_of_def by auto
himmelma@35172
   671
himmelma@35172
   672
lemma division_of_finite: "s division_of i \<Longrightarrow> finite s"
himmelma@35172
   673
  unfolding division_of_def by auto
himmelma@35172
   674
himmelma@35172
   675
lemma division_of_self[intro]: "{a..b} \<noteq> {} \<Longrightarrow> {{a..b}} division_of {a..b}"
himmelma@35172
   676
  unfolding division_of_def by auto
himmelma@35172
   677
himmelma@35172
   678
lemma division_of_trivial[simp]: "s division_of {} \<longleftrightarrow> s = {}" unfolding division_of_def by auto 
himmelma@35172
   679
wenzelm@49698
   680
lemma division_of_sing[simp]:
wenzelm@49698
   681
  "s division_of {a..a::'a::ordered_euclidean_space} \<longleftrightarrow> s = {{a..a}}" (is "?l = ?r")
wenzelm@49698
   682
proof
wenzelm@49698
   683
  assume ?r
wenzelm@49698
   684
  moreover {
wenzelm@49698
   685
    assume "s = {{a}}"
wenzelm@49698
   686
    moreover fix k assume "k\<in>s" 
wenzelm@49698
   687
    ultimately have"\<exists>x y. k = {x..y}"
wenzelm@49698
   688
      apply (rule_tac x=a in exI)+ unfolding interval_sing by auto
wenzelm@49698
   689
  }
wenzelm@49698
   690
  ultimately show ?l unfolding division_of_def interval_sing by auto
wenzelm@49698
   691
next
wenzelm@49698
   692
  assume ?l
wenzelm@49698
   693
  note as=conjunctD4[OF this[unfolded division_of_def interval_sing]]
himmelma@35172
   694
  { fix x assume x:"x\<in>s" have "x={a}" using as(2)[rule_format,OF x] by auto }
wenzelm@49698
   695
  moreover have "s \<noteq> {}" using as(4) by auto
wenzelm@49698
   696
  ultimately show ?r unfolding interval_sing by auto
wenzelm@49698
   697
qed
himmelma@35172
   698
himmelma@35172
   699
lemma elementary_empty: obtains p where "p division_of {}"
himmelma@35172
   700
  unfolding division_of_trivial by auto
himmelma@35172
   701
wenzelm@49698
   702
lemma elementary_interval: obtains p where "p division_of {a..b}"
wenzelm@49698
   703
  by (metis division_of_trivial division_of_self)
himmelma@35172
   704
himmelma@35172
   705
lemma division_contains: "s division_of i \<Longrightarrow> \<forall>x\<in>i. \<exists>k\<in>s. x \<in> k"
himmelma@35172
   706
  unfolding division_of_def by auto
himmelma@35172
   707
himmelma@35172
   708
lemma forall_in_division:
himmelma@35172
   709
 "d division_of i \<Longrightarrow> ((\<forall>x\<in>d. P x) \<longleftrightarrow> (\<forall>a b. {a..b} \<in> d \<longrightarrow> P {a..b}))"
nipkow@44890
   710
  unfolding division_of_def by fastforce
himmelma@35172
   711
himmelma@35172
   712
lemma division_of_subset: assumes "p division_of (\<Union>p)" "q \<subseteq> p" shows "q division_of (\<Union>q)"
wenzelm@49698
   713
  apply (rule division_ofI)
wenzelm@49698
   714
proof -
wenzelm@49698
   715
  note as=division_ofD[OF assms(1)]
wenzelm@49698
   716
  show "finite q"
wenzelm@49698
   717
    apply (rule finite_subset)
wenzelm@49698
   718
    using as(1) assms(2) apply auto
wenzelm@49698
   719
    done
wenzelm@49698
   720
  { fix k
wenzelm@49698
   721
    assume "k \<in> q"
wenzelm@49698
   722
    hence kp:"k\<in>p" using assms(2) by auto
wenzelm@49698
   723
    show "k\<subseteq>\<Union>q" using `k \<in> q` by auto
wenzelm@49698
   724
    show "\<exists>a b. k = {a..b}" using as(4)[OF kp]
wenzelm@49698
   725
      by auto show "k \<noteq> {}" using as(3)[OF kp] by auto }
wenzelm@49698
   726
  fix k1 k2
wenzelm@49698
   727
  assume "k1 \<in> q" "k2 \<in> q" "k1 \<noteq> k2"
wenzelm@49698
   728
  hence *: "k1\<in>p" "k2\<in>p" "k1\<noteq>k2" using assms(2) by auto
wenzelm@49698
   729
  show "interior k1 \<inter> interior k2 = {}" using as(5)[OF *] by auto
wenzelm@49698
   730
qed auto
wenzelm@49698
   731
wenzelm@49698
   732
lemma division_of_union_self[intro]: "p division_of s \<Longrightarrow> p division_of (\<Union>p)"
wenzelm@49698
   733
  unfolding division_of_def by auto
himmelma@35172
   734
wenzelm@49970
   735
lemma division_of_content_0:
wenzelm@49970
   736
  assumes "content {a..b} = 0" "d division_of {a..b}"
wenzelm@49970
   737
  shows "\<forall>k\<in>d. content k = 0"
wenzelm@49970
   738
  unfolding forall_in_division[OF assms(2)]
wenzelm@49970
   739
  apply(rule,rule,rule)
wenzelm@49970
   740
  apply(drule division_ofD(2)[OF assms(2)])
wenzelm@49970
   741
  apply(drule content_subset) unfolding assms(1)
wenzelm@49970
   742
proof -
wenzelm@49970
   743
  case goal1
wenzelm@49970
   744
  thus ?case using content_pos_le[of a b] by auto
wenzelm@49970
   745
qed
wenzelm@49970
   746
wenzelm@49970
   747
lemma division_inter:
wenzelm@49970
   748
  assumes "p1 division_of s1" "p2 division_of (s2::('a::ordered_euclidean_space) set)"
wenzelm@49970
   749
  shows "{k1 \<inter> k2 | k1 k2 .k1 \<in> p1 \<and> k2 \<in> p2 \<and> k1 \<inter> k2 \<noteq> {}} division_of (s1 \<inter> s2)"
wenzelm@49970
   750
  (is "?A' division_of _")
wenzelm@49970
   751
proof -
wenzelm@49970
   752
  let ?A = "{s. s \<in>  (\<lambda>(k1,k2). k1 \<inter> k2) ` (p1 \<times> p2) \<and> s \<noteq> {}}"
wenzelm@49970
   753
  have *:"?A' = ?A" by auto
wenzelm@49970
   754
  show ?thesis unfolding *
wenzelm@49970
   755
  proof (rule division_ofI)
wenzelm@49970
   756
    have "?A \<subseteq> (\<lambda>(x, y). x \<inter> y) ` (p1 \<times> p2)" by auto
wenzelm@49970
   757
    moreover have "finite (p1 \<times> p2)" using assms unfolding division_of_def by auto
wenzelm@49970
   758
    ultimately show "finite ?A" by auto
wenzelm@49970
   759
    have *:"\<And>s. \<Union>{x\<in>s. x \<noteq> {}} = \<Union>s" by auto
wenzelm@49970
   760
    show "\<Union>?A = s1 \<inter> s2"
wenzelm@49970
   761
      apply (rule set_eqI)
wenzelm@49970
   762
      unfolding * and Union_image_eq UN_iff
wenzelm@49970
   763
      using division_ofD(6)[OF assms(1)] and division_ofD(6)[OF assms(2)]
wenzelm@49970
   764
      apply auto
wenzelm@49970
   765
      done
wenzelm@49970
   766
    { fix k
wenzelm@49970
   767
      assume "k\<in>?A"
wenzelm@49970
   768
      then obtain k1 k2 where k: "k = k1 \<inter> k2" "k1\<in>p1" "k2\<in>p2" "k\<noteq>{}" by auto
wenzelm@49970
   769
      thus "k \<noteq> {}" by auto
wenzelm@49970
   770
      show "k \<subseteq> s1 \<inter> s2"
wenzelm@49970
   771
        using division_ofD(2)[OF assms(1) k(2)] and division_ofD(2)[OF assms(2) k(3)]
wenzelm@49970
   772
        unfolding k by auto
wenzelm@49970
   773
      guess a1 using division_ofD(4)[OF assms(1) k(2)] ..
wenzelm@49970
   774
      then guess b1 .. note ab1=this
wenzelm@49970
   775
      guess a2 using division_ofD(4)[OF assms(2) k(3)] ..
wenzelm@49970
   776
      then guess b2 .. note ab2=this
wenzelm@49970
   777
      show "\<exists>a b. k = {a..b}"
wenzelm@49970
   778
        unfolding k ab1 ab2 unfolding inter_interval by auto }
wenzelm@49970
   779
    fix k1 k2
wenzelm@49970
   780
    assume "k1\<in>?A"
wenzelm@49970
   781
    then obtain x1 y1 where k1:"k1 = x1 \<inter> y1" "x1\<in>p1" "y1\<in>p2" "k1\<noteq>{}" by auto
wenzelm@49970
   782
    assume "k2\<in>?A"
wenzelm@49970
   783
    then obtain x2 y2 where k2:"k2 = x2 \<inter> y2" "x2\<in>p1" "y2\<in>p2" "k2\<noteq>{}" by auto
wenzelm@49970
   784
    assume "k1 \<noteq> k2"
wenzelm@49970
   785
    hence th:"x1\<noteq>x2 \<or> y1\<noteq>y2" unfolding k1 k2 by auto
wenzelm@49970
   786
    have *:"(interior x1 \<inter> interior x2 = {} \<or> interior y1 \<inter> interior y2 = {}) \<Longrightarrow>
himmelma@35172
   787
      interior(x1 \<inter> y1) \<subseteq> interior(x1) \<Longrightarrow> interior(x1 \<inter> y1) \<subseteq> interior(y1) \<Longrightarrow>
himmelma@35172
   788
      interior(x2 \<inter> y2) \<subseteq> interior(x2) \<Longrightarrow> interior(x2 \<inter> y2) \<subseteq> interior(y2)
himmelma@35172
   789
      \<Longrightarrow> interior(x1 \<inter> y1) \<inter> interior(x2 \<inter> y2) = {}" by auto
wenzelm@49970
   790
    show "interior k1 \<inter> interior k2 = {}"
wenzelm@49970
   791
      unfolding k1 k2
wenzelm@49970
   792
      apply (rule *)
wenzelm@49970
   793
      defer
wenzelm@49970
   794
      apply (rule_tac[1-4] interior_mono)
wenzelm@49970
   795
      using division_ofD(5)[OF assms(1) k1(2) k2(2)]
wenzelm@49970
   796
      using division_ofD(5)[OF assms(2) k1(3) k2(3)]
wenzelm@49970
   797
      using th apply auto done
wenzelm@49970
   798
  qed
wenzelm@49970
   799
qed
wenzelm@49970
   800
wenzelm@49970
   801
lemma division_inter_1:
wenzelm@49970
   802
  assumes "d division_of i" "{a..b::'a::ordered_euclidean_space} \<subseteq> i"
wenzelm@49970
   803
  shows "{ {a..b} \<inter> k |k. k \<in> d \<and> {a..b} \<inter> k \<noteq> {} } division_of {a..b}"
wenzelm@49970
   804
proof (cases "{a..b} = {}")
wenzelm@49970
   805
  case True
wenzelm@49970
   806
  show ?thesis unfolding True and division_of_trivial by auto
wenzelm@49970
   807
next
wenzelm@49970
   808
  case False
wenzelm@49970
   809
  have *: "{a..b} \<inter> i = {a..b}" using assms(2) by auto
wenzelm@49970
   810
  show ?thesis using division_inter[OF division_of_self[OF False] assms(1)] unfolding * by auto
wenzelm@49970
   811
qed
wenzelm@49970
   812
wenzelm@49970
   813
lemma elementary_inter:
wenzelm@49970
   814
  assumes "p1 division_of s" "p2 division_of (t::('a::ordered_euclidean_space) set)"
himmelma@35172
   815
  shows "\<exists>p. p division_of (s \<inter> t)"
wenzelm@49970
   816
  by (rule, rule division_inter[OF assms])
wenzelm@49970
   817
wenzelm@49970
   818
lemma elementary_inters:
wenzelm@49970
   819
  assumes "finite f" "f\<noteq>{}" "\<forall>s\<in>f. \<exists>p. p division_of (s::('a::ordered_euclidean_space) set)"
wenzelm@49970
   820
  shows "\<exists>p. p division_of (\<Inter> f)"
wenzelm@49970
   821
  using assms
wenzelm@49970
   822
proof (induct f rule: finite_induct)
wenzelm@49970
   823
  case (insert x f)
wenzelm@49970
   824
  show ?case
wenzelm@49970
   825
  proof (cases "f = {}")
wenzelm@49970
   826
    case True
wenzelm@49970
   827
    thus ?thesis unfolding True using insert by auto
wenzelm@49970
   828
  next
wenzelm@49970
   829
    case False
wenzelm@49970
   830
    guess p using insert(3)[OF False insert(5)[unfolded ball_simps,THEN conjunct2]] ..
wenzelm@49970
   831
    moreover guess px using insert(5)[rule_format,OF insertI1] ..
wenzelm@49970
   832
    ultimately show ?thesis
wenzelm@49970
   833
      unfolding Inter_insert
wenzelm@49970
   834
      apply (rule_tac elementary_inter)
wenzelm@49970
   835
      apply assumption
wenzelm@49970
   836
      apply assumption
wenzelm@49970
   837
      done
wenzelm@49970
   838
  qed
wenzelm@49970
   839
qed auto
himmelma@35172
   840
himmelma@35172
   841
lemma division_disjoint_union:
himmelma@35172
   842
  assumes "p1 division_of s1" "p2 division_of s2" "interior s1 \<inter> interior s2 = {}"
himmelma@35172
   843
  shows "(p1 \<union> p2) division_of (s1 \<union> s2)" proof(rule division_ofI) 
himmelma@35172
   844
  note d1 = division_ofD[OF assms(1)] and d2 = division_ofD[OF assms(2)]
himmelma@35172
   845
  show "finite (p1 \<union> p2)" using d1(1) d2(1) by auto
himmelma@35172
   846
  show "\<Union>(p1 \<union> p2) = s1 \<union> s2" using d1(6) d2(6) by auto
himmelma@35172
   847
  { fix k1 k2 assume as:"k1 \<in> p1 \<union> p2" "k2 \<in> p1 \<union> p2" "k1 \<noteq> k2" moreover let ?g="interior k1 \<inter> interior k2 = {}"
huffman@44522
   848
  { assume as:"k1\<in>p1" "k2\<in>p2" have ?g using interior_mono[OF d1(2)[OF as(1)]] interior_mono[OF d2(2)[OF as(2)]]
himmelma@35172
   849
      using assms(3) by blast } moreover
huffman@44522
   850
  { assume as:"k1\<in>p2" "k2\<in>p1" have ?g using interior_mono[OF d1(2)[OF as(2)]] interior_mono[OF d2(2)[OF as(1)]]
himmelma@35172
   851
      using assms(3) by blast} ultimately
himmelma@35172
   852
  show ?g using d1(5)[OF _ _ as(3)] and d2(5)[OF _ _ as(3)] by auto }
himmelma@35172
   853
  fix k assume k:"k \<in> p1 \<union> p2"  show "k \<subseteq> s1 \<union> s2" using k d1(2) d2(2) by auto
himmelma@35172
   854
  show "k \<noteq> {}" using k d1(3) d2(3) by auto show "\<exists>a b. k = {a..b}" using k d1(4) d2(4) by auto qed
himmelma@35172
   855
himmelma@35172
   856
lemma partial_division_extend_1:
hoelzl@37489
   857
  assumes "{c..d} \<subseteq> {a..b::'a::ordered_euclidean_space}" "{c..d} \<noteq> {}"
himmelma@35172
   858
  obtains p where "p division_of {a..b}" "{c..d} \<in> p"
hoelzl@37489
   859
proof- def n \<equiv> "DIM('a)" have n:"1 \<le> n" "0 < n" "n \<noteq> 0" unfolding n_def using DIM_positive[where 'a='a] by auto
hoelzl@37489
   860
  guess \<pi> using ex_bij_betw_nat_finite_1[OF finite_lessThan[of "DIM('a)"]] .. note \<pi>=this
himmelma@35172
   861
  def \<pi>' \<equiv> "inv_into {1..n} \<pi>"
hoelzl@37489
   862
  have \<pi>':"bij_betw \<pi>' {..<DIM('a)} {1..n}" using bij_betw_inv_into[OF \<pi>] unfolding \<pi>'_def n_def by auto
hoelzl@37489
   863
  hence \<pi>'i:"\<And>i. i<DIM('a) \<Longrightarrow> \<pi>' i \<in> {1..n}" unfolding bij_betw_def by auto 
hoelzl@37489
   864
  have \<pi>i:"\<And>i. i\<in>{1..n} \<Longrightarrow> \<pi> i <DIM('a)" using \<pi> unfolding bij_betw_def n_def by auto 
hoelzl@37489
   865
  have \<pi>\<pi>'[simp]:"\<And>i. i<DIM('a) \<Longrightarrow> \<pi> (\<pi>' i) = i" unfolding \<pi>'_def
hoelzl@37489
   866
    apply(rule f_inv_into_f) unfolding n_def using \<pi> unfolding bij_betw_def by auto
hoelzl@37489
   867
  have \<pi>'\<pi>[simp]:"\<And>i. i\<in>{1..n} \<Longrightarrow> \<pi>' (\<pi> i) = i" unfolding \<pi>'_def apply(rule inv_into_f_eq)
hoelzl@37489
   868
    using \<pi> unfolding n_def bij_betw_def by auto
himmelma@35172
   869
  have "{c..d} \<noteq> {}" using assms by auto
hoelzl@37489
   870
  let ?p1 = "\<lambda>l. {(\<chi>\<chi> i. if \<pi>' i < l then c$$i else a$$i)::'a .. (\<chi>\<chi> i. if \<pi>' i < l then d$$i else if \<pi>' i = l then c$$\<pi> l else b$$i)}"
hoelzl@37489
   871
  let ?p2 = "\<lambda>l. {(\<chi>\<chi> i. if \<pi>' i < l then c$$i else if \<pi>' i = l then d$$\<pi> l else a$$i)::'a .. (\<chi>\<chi> i. if \<pi>' i < l then d$$i else b$$i)}"
himmelma@35172
   872
  let ?p =  "{?p1 l |l. l \<in> {1..n+1}} \<union> {?p2 l |l. l \<in> {1..n+1}}"
hoelzl@37489
   873
  have abcd:"\<And>i. i<DIM('a) \<Longrightarrow> a $$ i \<le> c $$ i \<and> c$$i \<le> d$$i \<and> d $$ i \<le> b $$ i" using assms
hoelzl@37489
   874
    unfolding subset_interval interval_eq_empty by auto
himmelma@35172
   875
  show ?thesis apply(rule that[of ?p]) apply(rule division_ofI)
hoelzl@37489
   876
  proof- have "\<And>i. i<DIM('a) \<Longrightarrow> \<pi>' i < Suc n"
hoelzl@37489
   877
    proof(rule ccontr,unfold not_less) fix i assume i:"i<DIM('a)" and "Suc n \<le> \<pi>' i"
hoelzl@37489
   878
      hence "\<pi>' i \<notin> {1..n}" by auto thus False using \<pi>' i unfolding bij_betw_def by auto
hoelzl@37489
   879
    qed hence "c = (\<chi>\<chi> i. if \<pi>' i < Suc n then c $$ i else a $$ i)"
hoelzl@37489
   880
        "d = (\<chi>\<chi> i. if \<pi>' i < Suc n then d $$ i else if \<pi>' i = n + 1 then c $$ \<pi> (n + 1) else b $$ i)"
hoelzl@37489
   881
      unfolding euclidean_eq[where 'a='a] using \<pi>' unfolding bij_betw_def by auto
himmelma@35172
   882
    thus cdp:"{c..d} \<in> ?p" apply-apply(rule UnI1) unfolding mem_Collect_eq apply(rule_tac x="n + 1" in exI) by auto
himmelma@35172
   883
    have "\<And>l. l\<in>{1..n+1} \<Longrightarrow> ?p1 l \<subseteq> {a..b}"  "\<And>l. l\<in>{1..n+1} \<Longrightarrow> ?p2 l \<subseteq> {a..b}"
himmelma@35172
   884
      unfolding subset_eq apply(rule_tac[!] ballI,rule_tac[!] ccontr)
himmelma@35172
   885
    proof- fix l assume l:"l\<in>{1..n+1}" fix x assume "x\<notin>{a..b}"
hoelzl@37489
   886
      then guess i unfolding mem_interval not_all not_imp .. note i=conjunctD2[OF this]
himmelma@35172
   887
      show "x \<in> ?p1 l \<Longrightarrow> False" "x \<in> ?p2 l \<Longrightarrow> False" unfolding mem_interval apply(erule_tac[!] x=i in allE)
himmelma@35172
   888
        apply(case_tac[!] "\<pi>' i < l", case_tac[!] "\<pi>' i = l") using abcd[of i] i by auto 
himmelma@35172
   889
    qed moreover have "\<And>x. x \<in> {a..b} \<Longrightarrow> x \<in> \<Union>?p"
himmelma@35172
   890
    proof- fix x assume x:"x\<in>{a..b}"
himmelma@35172
   891
      { presume "x\<notin>{c..d} \<Longrightarrow> x \<in> \<Union>?p" thus "x \<in> \<Union>?p" using cdp by blast }
hoelzl@37489
   892
      let ?M = "{i. i\<in>{1..n+1} \<and> \<not> (c $$ \<pi> i \<le> x $$ \<pi> i \<and> x $$ \<pi> i \<le> d $$ \<pi> i)}"
hoelzl@37489
   893
      assume "x\<notin>{c..d}" then guess i0 unfolding mem_interval not_all not_imp ..
himmelma@35172
   894
      hence "\<pi>' i0 \<in> ?M" using \<pi>' unfolding bij_betw_def by(auto intro!:le_SucI)
himmelma@35172
   895
      hence M:"finite ?M" "?M \<noteq> {}" by auto
himmelma@35172
   896
      def l \<equiv> "Min ?M" note l = Min_less_iff[OF M,unfolded l_def[symmetric]] Min_in[OF M,unfolded mem_Collect_eq l_def[symmetric]]
himmelma@35172
   897
        Min_gr_iff[OF M,unfolded l_def[symmetric]]
himmelma@35172
   898
      have "x\<in>?p1 l \<or> x\<in>?p2 l" using l(2)[THEN conjunct2] unfolding de_Morgan_conj not_le
himmelma@35172
   899
        apply- apply(erule disjE) apply(rule disjI1) defer apply(rule disjI2)
hoelzl@37489
   900
      proof- assume as:"x $$ \<pi> l < c $$ \<pi> l"
hoelzl@37489
   901
        show "x \<in> ?p1 l" unfolding mem_interval apply safe unfolding euclidean_lambda_beta'
hoelzl@37489
   902
        proof- case goal1 have "\<pi>' i \<in> {1..n}" using \<pi>' unfolding bij_betw_def not_le using goal1 by auto
himmelma@35172
   903
          thus ?case using as x[unfolded mem_interval,rule_format,of i]
hoelzl@37489
   904
            apply auto using l(3)[of "\<pi>' i"] using goal1 by(auto elim!:ballE[where x="\<pi>' i"])
hoelzl@37489
   905
        next case goal2 have "\<pi>' i \<in> {1..n}" using \<pi>' unfolding bij_betw_def not_le using goal2 by auto
hoelzl@37489
   906
          thus ?case using as x[unfolded mem_interval,rule_format,of i]
hoelzl@37489
   907
            apply auto using l(3)[of "\<pi>' i"] using goal2 by(auto elim!:ballE[where x="\<pi>' i"])
himmelma@35172
   908
        qed
hoelzl@37489
   909
      next assume as:"x $$ \<pi> l > d $$ \<pi> l"
hoelzl@37489
   910
        show "x \<in> ?p2 l" unfolding mem_interval apply safe unfolding euclidean_lambda_beta'
hoelzl@37489
   911
        proof- fix i assume i:"i<DIM('a)"
hoelzl@37489
   912
          have "\<pi>' i \<in> {1..n}" using \<pi>' unfolding bij_betw_def not_le using i by auto
hoelzl@37489
   913
          thus "(if \<pi>' i < l then c $$ i else if \<pi>' i = l then d $$ \<pi> l else a $$ i) \<le> x $$ i"
hoelzl@37489
   914
            "x $$ i \<le> (if \<pi>' i < l then d $$ i else b $$ i)"
hoelzl@37489
   915
            using as x[unfolded mem_interval,rule_format,of i]
hoelzl@37489
   916
            apply auto using l(3)[of "\<pi>' i"] i by(auto elim!:ballE[where x="\<pi>' i"])
himmelma@35172
   917
        qed qed
himmelma@35172
   918
      thus "x \<in> \<Union>?p" using l(2) by blast 
himmelma@35172
   919
    qed ultimately show "\<Union>?p = {a..b}" apply-apply(rule) defer apply(rule) by(assumption,blast)
himmelma@35172
   920
    
himmelma@35172
   921
    show "finite ?p" by auto
himmelma@35172
   922
    fix k assume k:"k\<in>?p" then obtain l where l:"k = ?p1 l \<or> k = ?p2 l" "l \<in> {1..n + 1}" by auto
himmelma@35172
   923
    show "k\<subseteq>{a..b}" apply(rule,unfold mem_interval,rule,rule) 
hoelzl@37489
   924
    proof fix i x assume i:"i<DIM('a)" assume "x \<in> k" moreover have "\<pi>' i < l \<or> \<pi>' i = l \<or> \<pi>' i > l" by auto
hoelzl@37489
   925
      ultimately show "a$$i \<le> x$$i" "x$$i \<le> b$$i" using abcd[of i] using l using i
huffman@44457
   926
        by(auto elim!:allE[where x=i] simp add:eucl_le[where 'a='a]) (* FIXME: SLOW *)
himmelma@35172
   927
    qed have "\<And>l. ?p1 l \<noteq> {}" "\<And>l. ?p2 l \<noteq> {}" unfolding interval_eq_empty not_ex apply(rule_tac[!] allI)
himmelma@35172
   928
    proof- case goal1 thus ?case using abcd[of x] by auto
himmelma@35172
   929
    next   case goal2 thus ?case using abcd[of x] by auto
himmelma@35172
   930
    qed thus "k \<noteq> {}" using k by auto
himmelma@35172
   931
    show "\<exists>a b. k = {a..b}" using k by auto
himmelma@35172
   932
    fix k' assume k':"k' \<in> ?p" "k \<noteq> k'" then obtain l' where l':"k' = ?p1 l' \<or> k' = ?p2 l'" "l' \<in> {1..n + 1}" by auto
himmelma@35172
   933
    { fix k k' l l'
himmelma@35172
   934
      assume k:"k\<in>?p" and l:"k = ?p1 l \<or> k = ?p2 l" "l \<in> {1..n + 1}" 
himmelma@35172
   935
      assume k':"k' \<in> ?p" "k \<noteq> k'" and  l':"k' = ?p1 l' \<or> k' = ?p2 l'" "l' \<in> {1..n + 1}" 
himmelma@35172
   936
      assume "l \<le> l'" fix x
himmelma@35172
   937
      have "x \<notin> interior k \<inter> interior k'" 
himmelma@35172
   938
      proof(rule,cases "l' = n+1") assume x:"x \<in> interior k \<inter> interior k'"
hoelzl@37489
   939
        case True hence "\<And>i. i<DIM('a) \<Longrightarrow> \<pi>' i < l'" using \<pi>'i using l' by(auto simp add:less_Suc_eq_le)
hoelzl@37489
   940
        hence *:"\<And> P Q. (\<chi>\<chi> i. if \<pi>' i < l' then P i else Q i) = ((\<chi>\<chi> i. P i)::'a)" apply-apply(subst euclidean_eq) by auto
hoelzl@37489
   941
        hence k':"k' = {c..d}" using l'(1) unfolding * by auto
himmelma@35172
   942
        have ln:"l < n + 1" 
himmelma@35172
   943
        proof(rule ccontr) case goal1 hence l2:"l = n+1" using l by auto
hoelzl@37489
   944
          hence "\<And>i. i<DIM('a) \<Longrightarrow> \<pi>' i < l" using \<pi>'i by(auto simp add:less_Suc_eq_le)
hoelzl@37489
   945
          hence *:"\<And> P Q. (\<chi>\<chi> i. if \<pi>' i < l then P i else Q i) = ((\<chi>\<chi> i. P i)::'a)" apply-apply(subst euclidean_eq) by auto
hoelzl@37489
   946
          hence "k = {c..d}" using l(1) \<pi>'i unfolding * by(auto)
himmelma@35172
   947
          thus False using `k\<noteq>k'` k' by auto
himmelma@35172
   948
        qed have **:"\<pi>' (\<pi> l) = l" using \<pi>'\<pi>[of l] using l ln by auto
hoelzl@37489
   949
        have "x $$ \<pi> l < c $$ \<pi> l \<or> d $$ \<pi> l < x $$ \<pi> l" using l(1) apply-
himmelma@35172
   950
        proof(erule disjE)
himmelma@35172
   951
          assume as:"k = ?p1 l" note * = conjunct1[OF x[unfolded as Int_iff interior_closed_interval mem_interval],rule_format]
hoelzl@37489
   952
          show ?thesis using *[of "\<pi> l"] using ln l(2) using \<pi>i[of l] by(auto simp add:** not_less)
himmelma@35172
   953
        next assume as:"k = ?p2 l" note * = conjunct1[OF x[unfolded as Int_iff interior_closed_interval mem_interval],rule_format]
hoelzl@37489
   954
          show ?thesis using *[of "\<pi> l"] using ln l(2) using \<pi>i[of l] unfolding ** by auto
himmelma@35172
   955
        qed thus False using x unfolding k' unfolding Int_iff interior_closed_interval mem_interval
himmelma@35172
   956
          by(auto elim!:allE[where x="\<pi> l"])
himmelma@35172
   957
      next case False hence "l < n + 1" using l'(2) using `l\<le>l'` by auto
himmelma@35172
   958
        hence ln:"l \<in> {1..n}" "l' \<in> {1..n}" using l l' False by auto
himmelma@35172
   959
        note \<pi>l = \<pi>'\<pi>[OF ln(1)] \<pi>'\<pi>[OF ln(2)]
himmelma@35172
   960
        assume x:"x \<in> interior k \<inter> interior k'"
himmelma@35172
   961
        show False using l(1) l'(1) apply-
himmelma@35172
   962
        proof(erule_tac[!] disjE)+
himmelma@35172
   963
          assume as:"k = ?p1 l" "k' = ?p1 l'"
hoelzl@37489
   964
          note * = conjunctD2[OF x[unfolded as Int_iff interior_closed_interval mem_interval],rule_format]
himmelma@35172
   965
          have "l \<noteq> l'" using k'(2)[unfolded as] by auto
hoelzl@37489
   966
          thus False using *[of "\<pi> l'"] *[of "\<pi> l"] ln using \<pi>i[OF ln(1)] \<pi>i[OF ln(2)] apply(cases "l<l'")
hoelzl@37489
   967
            by(auto simp add:euclidean_lambda_beta' \<pi>l \<pi>i n_def)
himmelma@35172
   968
        next assume as:"k = ?p2 l" "k' = ?p2 l'"
himmelma@35172
   969
          note * = conjunctD2[OF x[unfolded as Int_iff interior_closed_interval mem_interval],rule_format]
himmelma@35172
   970
          have "l \<noteq> l'" apply(rule) using k'(2)[unfolded as] by auto
hoelzl@37489
   971
          thus False using *[of "\<pi> l"] *[of "\<pi> l'"]  `l \<le> l'` ln by(auto simp add:euclidean_lambda_beta' \<pi>l \<pi>i n_def)
himmelma@35172
   972
        next assume as:"k = ?p1 l" "k' = ?p2 l'"
himmelma@35172
   973
          note * = conjunctD2[OF x[unfolded as Int_iff interior_closed_interval mem_interval],rule_format]
hoelzl@37489
   974
          show False using abcd[of "\<pi> l'"] using *[of "\<pi> l"] *[of "\<pi> l'"]  `l \<le> l'` ln apply(cases "l=l'")
hoelzl@37489
   975
            by(auto simp add:euclidean_lambda_beta' \<pi>l \<pi>i n_def)
himmelma@35172
   976
        next assume as:"k = ?p2 l" "k' = ?p1 l'"
himmelma@35172
   977
          note * = conjunctD2[OF x[unfolded as Int_iff interior_closed_interval mem_interval],rule_format]
hoelzl@37489
   978
          show False using *[of "\<pi> l"] *[of "\<pi> l'"] ln `l \<le> l'` apply(cases "l=l'") using abcd[of "\<pi> l'"] 
hoelzl@37489
   979
            by(auto simp add:euclidean_lambda_beta' \<pi>l \<pi>i n_def)
himmelma@35172
   980
        qed qed } 
himmelma@35172
   981
    from this[OF k l k' l'] this[OF k'(1) l' k _ l] have "\<And>x. x \<notin> interior k \<inter> interior k'"
himmelma@35172
   982
      apply - apply(cases "l' \<le> l") using k'(2) by auto            
himmelma@35172
   983
    thus "interior k \<inter> interior k' = {}" by auto        
himmelma@35172
   984
qed qed
himmelma@35172
   985
himmelma@35172
   986
lemma partial_division_extend_interval: assumes "p division_of (\<Union>p)" "(\<Union>p) \<subseteq> {a..b}"
hoelzl@37489
   987
  obtains q where "p \<subseteq> q" "q division_of {a..b::'a::ordered_euclidean_space}" proof(cases "p = {}")
himmelma@35172
   988
  case True guess q apply(rule elementary_interval[of a b]) .
himmelma@35172
   989
  thus ?thesis apply- apply(rule that[of q]) unfolding True by auto next
himmelma@35172
   990
  case False note p = division_ofD[OF assms(1)]
himmelma@35172
   991
  have *:"\<forall>k\<in>p. \<exists>q. q division_of {a..b} \<and> k\<in>q" proof case goal1
himmelma@35172
   992
    guess c using p(4)[OF goal1] .. then guess d .. note cd_ = this
himmelma@35172
   993
    have *:"{c..d} \<subseteq> {a..b}" "{c..d} \<noteq> {}" using p(2,3)[OF goal1, unfolded cd_] using assms(2) by auto
himmelma@35172
   994
    guess q apply(rule partial_division_extend_1[OF *]) . thus ?case unfolding cd_ by auto qed
himmelma@35172
   995
  guess q using bchoice[OF *] .. note q = conjunctD2[OF this[rule_format]]
himmelma@35172
   996
  have "\<And>x. x\<in>p \<Longrightarrow> \<exists>d. d division_of \<Union>(q x - {x})" apply(rule,rule_tac p="q x" in division_of_subset) proof-
himmelma@35172
   997
    fix x assume x:"x\<in>p" show "q x division_of \<Union>q x" apply-apply(rule division_ofI)
himmelma@35172
   998
      using division_ofD[OF q(1)[OF x]] by auto show "q x - {x} \<subseteq> q x" by auto qed
himmelma@35172
   999
  hence "\<exists>d. d division_of \<Inter> ((\<lambda>i. \<Union>(q i - {i})) ` p)" apply- apply(rule elementary_inters)
himmelma@35172
  1000
    apply(rule finite_imageI[OF p(1)]) unfolding image_is_empty apply(rule False) by auto
himmelma@35172
  1001
  then guess d .. note d = this
himmelma@35172
  1002
  show ?thesis apply(rule that[of "d \<union> p"]) proof-
himmelma@35172
  1003
    have *:"\<And>s f t. s \<noteq> {} \<Longrightarrow> (\<forall>i\<in>s. f i \<union> i = t) \<Longrightarrow> t = \<Inter> (f ` s) \<union> (\<Union>s)" by auto
himmelma@35172
  1004
    have *:"{a..b} = \<Inter> (\<lambda>i. \<Union>(q i - {i})) ` p \<union> \<Union>p" apply(rule *[OF False]) proof fix i assume i:"i\<in>p"
himmelma@35172
  1005
      show "\<Union>(q i - {i}) \<union> i = {a..b}" using division_ofD(6)[OF q(1)[OF i]] using q(2)[OF i] by auto qed
himmelma@35172
  1006
    show "d \<union> p division_of {a..b}" unfolding * apply(rule division_disjoint_union[OF d assms(1)])
himmelma@35172
  1007
      apply(rule inter_interior_unions_intervals) apply(rule p open_interior ballI)+ proof(assumption,rule)
himmelma@35172
  1008
      fix k assume k:"k\<in>p" have *:"\<And>u t s. u \<subseteq> s \<Longrightarrow> s \<inter> t = {} \<Longrightarrow> u \<inter> t = {}" by auto
himmelma@35172
  1009
      show "interior (\<Inter>(\<lambda>i. \<Union>(q i - {i})) ` p) \<inter> interior k = {}" apply(rule *[of _ "interior (\<Union>(q k - {k}))"])
wenzelm@41958
  1010
        defer apply(subst Int_commute) apply(rule inter_interior_unions_intervals) proof- note qk=division_ofD[OF q(1)[OF k]]
wenzelm@41958
  1011
        show "finite (q k - {k})" "open (interior k)"  "\<forall>t\<in>q k - {k}. \<exists>a b. t = {a..b}" using qk by auto
wenzelm@41958
  1012
        show "\<forall>t\<in>q k - {k}. interior k \<inter> interior t = {}" using qk(5) using q(2)[OF k] by auto
wenzelm@41958
  1013
        have *:"\<And>x s. x \<in> s \<Longrightarrow> \<Inter>s \<subseteq> x" by auto show "interior (\<Inter>(\<lambda>i. \<Union>(q i - {i})) ` p) \<subseteq> interior (\<Union>(q k - {k}))"
huffman@44522
  1014
          apply(rule interior_mono *)+ using k by auto qed qed qed auto qed
himmelma@35172
  1015
hoelzl@37489
  1016
lemma elementary_bounded[dest]: "p division_of s \<Longrightarrow> bounded (s::('a::ordered_euclidean_space) set)"
himmelma@35172
  1017
  unfolding division_of_def by(metis bounded_Union bounded_interval) 
himmelma@35172
  1018
hoelzl@37489
  1019
lemma elementary_subset_interval: "p division_of s \<Longrightarrow> \<exists>a b. s \<subseteq> {a..b::'a::ordered_euclidean_space}"
himmelma@35172
  1020
  by(meson elementary_bounded bounded_subset_closed_interval)
himmelma@35172
  1021
hoelzl@37489
  1022
lemma division_union_intervals_exists: assumes "{a..b::'a::ordered_euclidean_space} \<noteq> {}"
himmelma@35172
  1023
  obtains p where "(insert {a..b} p) division_of ({a..b} \<union> {c..d})" proof(cases "{c..d} = {}")
himmelma@35172
  1024
  case True show ?thesis apply(rule that[of "{}"]) unfolding True using assms by auto next
himmelma@35172
  1025
  case False note false=this show ?thesis proof(cases "{a..b} \<inter> {c..d} = {}")
himmelma@35172
  1026
  have *:"\<And>a b. {a,b} = {a} \<union> {b}" by auto
himmelma@35172
  1027
  case True show ?thesis apply(rule that[of "{{c..d}}"]) unfolding * apply(rule division_disjoint_union)
himmelma@35172
  1028
    using false True assms using interior_subset by auto next
himmelma@35172
  1029
  case False obtain u v where uv:"{a..b} \<inter> {c..d} = {u..v}" unfolding inter_interval by auto
himmelma@35172
  1030
  have *:"{u..v} \<subseteq> {c..d}" using uv by auto
himmelma@35172
  1031
  guess p apply(rule partial_division_extend_1[OF * False[unfolded uv]]) . note p=this division_ofD[OF this(1)]
himmelma@35172
  1032
  have *:"{a..b} \<union> {c..d} = {a..b} \<union> \<Union>(p - {{u..v}})" "\<And>x s. insert x s = {x} \<union> s" using p(8) unfolding uv[THEN sym] by auto
himmelma@35172
  1033
  show thesis apply(rule that[of "p - {{u..v}}"]) unfolding *(1) apply(subst *(2)) apply(rule division_disjoint_union)
himmelma@35172
  1034
    apply(rule,rule assms) apply(rule division_of_subset[of p]) apply(rule division_of_union_self[OF p(1)]) defer
himmelma@35172
  1035
    unfolding interior_inter[THEN sym] proof-
himmelma@35172
  1036
    have *:"\<And>cd p uv ab. p \<subseteq> cd \<Longrightarrow> ab \<inter> cd = uv \<Longrightarrow> ab \<inter> p = uv \<inter> p" by auto
himmelma@35172
  1037
    have "interior ({a..b} \<inter> \<Union>(p - {{u..v}})) = interior({u..v} \<inter> \<Union>(p - {{u..v}}))" 
himmelma@35172
  1038
      apply(rule arg_cong[of _ _ interior]) apply(rule *[OF _ uv]) using p(8) by auto
himmelma@35172
  1039
    also have "\<dots> = {}" unfolding interior_inter apply(rule inter_interior_unions_intervals) using p(6) p(7)[OF p(2)] p(3) by auto
himmelma@35172
  1040
    finally show "interior ({a..b} \<inter> \<Union>(p - {{u..v}})) = {}" by assumption qed auto qed qed
himmelma@35172
  1041
himmelma@35172
  1042
lemma division_of_unions: assumes "finite f"  "\<And>p. p\<in>f \<Longrightarrow> p division_of (\<Union>p)"
himmelma@35172
  1043
  "\<And>k1 k2. \<lbrakk>k1 \<in> \<Union>f; k2 \<in> \<Union>f; k1 \<noteq> k2\<rbrakk> \<Longrightarrow> interior k1 \<inter> interior k2 = {}"
himmelma@35172
  1044
  shows "\<Union>f division_of \<Union>\<Union>f" apply(rule division_ofI) prefer 5 apply(rule assms(3)|assumption)+
himmelma@35172
  1045
  apply(rule finite_Union assms(1))+ prefer 3 apply(erule UnionE) apply(rule_tac s=X in division_ofD(3)[OF assms(2)])
himmelma@35172
  1046
  using division_ofD[OF assms(2)] by auto
himmelma@35172
  1047
  
himmelma@35172
  1048
lemma elementary_union_interval: assumes "p division_of \<Union>p"
hoelzl@37489
  1049
  obtains q where "q division_of ({a..b::'a::ordered_euclidean_space} \<union> \<Union>p)" proof-
himmelma@35172
  1050
  note assm=division_ofD[OF assms]
himmelma@35172
  1051
  have lem1:"\<And>f s. \<Union>\<Union> (f ` s) = \<Union>(\<lambda>x.\<Union>(f x)) ` s" by auto
himmelma@35172
  1052
  have lem2:"\<And>f s. f \<noteq> {} \<Longrightarrow> \<Union>{s \<union> t |t. t \<in> f} = s \<union> \<Union>f" by auto
himmelma@35172
  1053
{ presume "p={} \<Longrightarrow> thesis" "{a..b} = {} \<Longrightarrow> thesis" "{a..b} \<noteq> {} \<Longrightarrow> interior {a..b} = {} \<Longrightarrow> thesis"
himmelma@35172
  1054
    "p\<noteq>{} \<Longrightarrow> interior {a..b}\<noteq>{} \<Longrightarrow> {a..b} \<noteq> {} \<Longrightarrow> thesis"
himmelma@35172
  1055
  thus thesis by auto
himmelma@35172
  1056
next assume as:"p={}" guess p apply(rule elementary_interval[of a b]) .
himmelma@35172
  1057
  thus thesis apply(rule_tac that[of p]) unfolding as by auto 
himmelma@35172
  1058
next assume as:"{a..b}={}" show thesis apply(rule that) unfolding as using assms by auto
himmelma@35172
  1059
next assume as:"interior {a..b} = {}" "{a..b} \<noteq> {}"
himmelma@35172
  1060
  show thesis apply(rule that[of "insert {a..b} p"],rule division_ofI)
himmelma@35172
  1061
    unfolding finite_insert apply(rule assm(1)) unfolding Union_insert  
nipkow@44890
  1062
    using assm(2-4) as apply- by(fastforce dest: assm(5))+
himmelma@35172
  1063
next assume as:"p \<noteq> {}" "interior {a..b} \<noteq> {}" "{a..b}\<noteq>{}"
himmelma@35172
  1064
  have "\<forall>k\<in>p. \<exists>q. (insert {a..b} q) division_of ({a..b} \<union> k)" proof case goal1
himmelma@35172
  1065
    from assm(4)[OF this] guess c .. then guess d ..
himmelma@35172
  1066
    thus ?case apply-apply(rule division_union_intervals_exists[OF as(3),of c d]) by auto
himmelma@35172
  1067
  qed from bchoice[OF this] guess q .. note q=division_ofD[OF this[rule_format]]
himmelma@35172
  1068
  let ?D = "\<Union>{insert {a..b} (q k) | k. k \<in> p}"
himmelma@35172
  1069
  show thesis apply(rule that[of "?D"]) proof(rule division_ofI)
himmelma@35172
  1070
    have *:"{insert {a..b} (q k) |k. k \<in> p} = (\<lambda>k. insert {a..b} (q k)) ` p" by auto
himmelma@35172
  1071
    show "finite ?D" apply(rule finite_Union) unfolding * apply(rule finite_imageI) using assm(1) q(1) by auto
himmelma@35172
  1072
    show "\<Union>?D = {a..b} \<union> \<Union>p" unfolding * lem1 unfolding lem2[OF as(1), of "{a..b}",THEN sym]
himmelma@35172
  1073
      using q(6) by auto
himmelma@35172
  1074
    fix k assume k:"k\<in>?D" thus " k \<subseteq> {a..b} \<union> \<Union>p" using q(2) by auto
himmelma@35172
  1075
    show "k \<noteq> {}" using q(3) k by auto show "\<exists>a b. k = {a..b}" using q(4) k by auto
himmelma@35172
  1076
    fix k' assume k':"k'\<in>?D" "k\<noteq>k'"
himmelma@35172
  1077
    obtain x  where x: "k \<in>insert {a..b} (q x)"  "x\<in>p"  using k  by auto
himmelma@35172
  1078
    obtain x' where x':"k'\<in>insert {a..b} (q x')" "x'\<in>p" using k' by auto
himmelma@35172
  1079
    show "interior k \<inter> interior k' = {}" proof(cases "x=x'")
himmelma@35172
  1080
      case True show ?thesis apply(rule q(5)) using x x' k' unfolding True by auto
himmelma@35172
  1081
    next case False 
himmelma@35172
  1082
      { presume "k = {a..b} \<Longrightarrow> ?thesis" "k' = {a..b} \<Longrightarrow> ?thesis" 
himmelma@35172
  1083
        "k \<noteq> {a..b} \<Longrightarrow> k' \<noteq> {a..b} \<Longrightarrow> ?thesis"
himmelma@35172
  1084
        thus ?thesis by auto }
himmelma@35172
  1085
      { assume as':"k  = {a..b}" show ?thesis apply(rule q(5)) using x' k'(2) unfolding as' by auto }
himmelma@35172
  1086
      { assume as':"k' = {a..b}" show ?thesis apply(rule q(5)) using x  k'(2) unfolding as' by auto }
himmelma@35172
  1087
      assume as':"k \<noteq> {a..b}" "k' \<noteq> {a..b}"
himmelma@35172
  1088
      guess c using q(4)[OF x(2,1)] .. then guess d .. note c_d=this
himmelma@35172
  1089
      have "interior k  \<inter> interior {a..b} = {}" apply(rule q(5)) using x  k'(2) using as' by auto
himmelma@35172
  1090
      hence "interior k \<subseteq> interior x" apply-
himmelma@35172
  1091
        apply(rule interior_subset_union_intervals[OF c_d _ as(2) q(2)[OF x(2,1)]]) by auto moreover
himmelma@35172
  1092
      guess c using q(4)[OF x'(2,1)] .. then guess d .. note c_d=this
himmelma@35172
  1093
      have "interior k' \<inter> interior {a..b} = {}" apply(rule q(5)) using x' k'(2) using as' by auto
himmelma@35172
  1094
      hence "interior k' \<subseteq> interior x'" apply-
himmelma@35172
  1095
        apply(rule interior_subset_union_intervals[OF c_d _ as(2) q(2)[OF x'(2,1)]]) by auto
himmelma@35172
  1096
      ultimately show ?thesis using assm(5)[OF x(2) x'(2) False] by auto
himmelma@35172
  1097
    qed qed } qed
himmelma@35172
  1098
himmelma@35172
  1099
lemma elementary_unions_intervals:
hoelzl@37489
  1100
  assumes "finite f" "\<And>s. s \<in> f \<Longrightarrow> \<exists>a b. s = {a..b::'a::ordered_euclidean_space}"
himmelma@35172
  1101
  obtains p where "p division_of (\<Union>f)" proof-
himmelma@35172
  1102
  have "\<exists>p. p division_of (\<Union>f)" proof(induct_tac f rule:finite_subset_induct) 
himmelma@35172
  1103
    show "\<exists>p. p division_of \<Union>{}" using elementary_empty by auto
himmelma@35172
  1104
    fix x F assume as:"finite F" "x \<notin> F" "\<exists>p. p division_of \<Union>F" "x\<in>f"
himmelma@35172
  1105
    from this(3) guess p .. note p=this
himmelma@35172
  1106
    from assms(2)[OF as(4)] guess a .. then guess b .. note ab=this
himmelma@35172
  1107
    have *:"\<Union>F = \<Union>p" using division_ofD[OF p] by auto
himmelma@35172
  1108
    show "\<exists>p. p division_of \<Union>insert x F" using elementary_union_interval[OF p[unfolded *], of a b]
himmelma@35172
  1109
      unfolding Union_insert ab * by auto
himmelma@35172
  1110
  qed(insert assms,auto) thus ?thesis apply-apply(erule exE,rule that) by auto qed
himmelma@35172
  1111
hoelzl@37489
  1112
lemma elementary_union: assumes "ps division_of s" "pt division_of (t::('a::ordered_euclidean_space) set)"
himmelma@35172
  1113
  obtains p where "p division_of (s \<union> t)"
himmelma@35172
  1114
proof- have "s \<union> t = \<Union>ps \<union> \<Union>pt" using assms unfolding division_of_def by auto
himmelma@35172
  1115
  hence *:"\<Union>(ps \<union> pt) = s \<union> t" by auto
himmelma@35172
  1116
  show ?thesis apply-apply(rule elementary_unions_intervals[of "ps\<union>pt"])
himmelma@35172
  1117
    unfolding * prefer 3 apply(rule_tac p=p in that)
himmelma@35172
  1118
    using assms[unfolded division_of_def] by auto qed
himmelma@35172
  1119
hoelzl@37489
  1120
lemma partial_division_extend: fixes t::"('a::ordered_euclidean_space) set"
himmelma@35172
  1121
  assumes "p division_of s" "q division_of t" "s \<subseteq> t"
himmelma@35172
  1122
  obtains r where "p \<subseteq> r" "r division_of t" proof-
himmelma@35172
  1123
  note divp = division_ofD[OF assms(1)] and divq = division_ofD[OF assms(2)]
himmelma@35172
  1124
  obtain a b where ab:"t\<subseteq>{a..b}" using elementary_subset_interval[OF assms(2)] by auto
himmelma@35172
  1125
  guess r1 apply(rule partial_division_extend_interval) apply(rule assms(1)[unfolded divp(6)[THEN sym]])
himmelma@35172
  1126
    apply(rule subset_trans) by(rule ab assms[unfolded divp(6)[THEN sym]])+  note r1 = this division_ofD[OF this(2)]
himmelma@35172
  1127
  guess p' apply(rule elementary_unions_intervals[of "r1 - p"]) using r1(3,6) by auto 
himmelma@35172
  1128
  then obtain r2 where r2:"r2 division_of (\<Union>(r1 - p)) \<inter> (\<Union>q)" 
himmelma@35172
  1129
    apply- apply(drule elementary_inter[OF _ assms(2)[unfolded divq(6)[THEN sym]]]) by auto
himmelma@35172
  1130
  { fix x assume x:"x\<in>t" "x\<notin>s"
himmelma@35172
  1131
    hence "x\<in>\<Union>r1" unfolding r1 using ab by auto
himmelma@35172
  1132
    then guess r unfolding Union_iff .. note r=this moreover
himmelma@35172
  1133
    have "r \<notin> p" proof assume "r\<in>p" hence "x\<in>s" using divp(2) r by auto
himmelma@35172
  1134
      thus False using x by auto qed
himmelma@35172
  1135
    ultimately have "x\<in>\<Union>(r1 - p)" by auto }
himmelma@35172
  1136
  hence *:"t = \<Union>p \<union> (\<Union>(r1 - p) \<inter> \<Union>q)" unfolding divp divq using assms(3) by auto
himmelma@35172
  1137
  show ?thesis apply(rule that[of "p \<union> r2"]) unfolding * defer apply(rule division_disjoint_union)
himmelma@35172
  1138
    unfolding divp(6) apply(rule assms r2)+
himmelma@35172
  1139
  proof- have "interior s \<inter> interior (\<Union>(r1-p)) = {}"
himmelma@35172
  1140
    proof(rule inter_interior_unions_intervals)
himmelma@35172
  1141
      show "finite (r1 - p)" "open (interior s)" "\<forall>t\<in>r1-p. \<exists>a b. t = {a..b}" using r1 by auto
himmelma@35172
  1142
      have *:"\<And>s. (\<And>x. x \<in> s \<Longrightarrow> False) \<Longrightarrow> s = {}" by auto
himmelma@35172
  1143
      show "\<forall>t\<in>r1-p. interior s \<inter> interior t = {}" proof(rule)
himmelma@35172
  1144
        fix m x assume as:"m\<in>r1-p"
himmelma@35172
  1145
        have "interior m \<inter> interior (\<Union>p) = {}" proof(rule inter_interior_unions_intervals)
himmelma@35172
  1146
          show "finite p" "open (interior m)" "\<forall>t\<in>p. \<exists>a b. t = {a..b}" using divp by auto
himmelma@35172
  1147
          show "\<forall>t\<in>p. interior m \<inter> interior t = {}" apply(rule, rule r1(7)) using as using r1 by auto
himmelma@35172
  1148
        qed thus "interior s \<inter> interior m = {}" unfolding divp by auto
himmelma@35172
  1149
      qed qed        
himmelma@35172
  1150
    thus "interior s \<inter> interior (\<Union>(r1-p) \<inter> (\<Union>q)) = {}" using interior_subset by auto
himmelma@35172
  1151
  qed auto qed
himmelma@35172
  1152
himmelma@35172
  1153
subsection {* Tagged (partial) divisions. *}
himmelma@35172
  1154
himmelma@35172
  1155
definition tagged_partial_division_of (infixr "tagged'_partial'_division'_of" 40) where
himmelma@35172
  1156
  "(s tagged_partial_division_of i) \<equiv>
himmelma@35172
  1157
        finite s \<and>
himmelma@35172
  1158
        (\<forall>x k. (x,k) \<in> s \<longrightarrow> x \<in> k \<and> k \<subseteq> i \<and> (\<exists>a b. k = {a..b})) \<and>
himmelma@35172
  1159
        (\<forall>x1 k1 x2 k2. (x1,k1) \<in> s \<and> (x2,k2) \<in> s \<and> ((x1,k1) \<noteq> (x2,k2))
himmelma@35172
  1160
                       \<longrightarrow> (interior(k1) \<inter> interior(k2) = {}))"
himmelma@35172
  1161
himmelma@35172
  1162
lemma tagged_partial_division_ofD[dest]: assumes "s tagged_partial_division_of i"
himmelma@35172
  1163
  shows "finite s" "\<And>x k. (x,k) \<in> s \<Longrightarrow> x \<in> k" "\<And>x k. (x,k) \<in> s \<Longrightarrow> k \<subseteq> i"
himmelma@35172
  1164
  "\<And>x k. (x,k) \<in> s \<Longrightarrow> \<exists>a b. k = {a..b}"
himmelma@35172
  1165
  "\<And>x1 k1 x2 k2. (x1,k1) \<in> s \<Longrightarrow> (x2,k2) \<in> s \<Longrightarrow> (x1,k1) \<noteq> (x2,k2) \<Longrightarrow> interior(k1) \<inter> interior(k2) = {}"
himmelma@35172
  1166
  using assms unfolding tagged_partial_division_of_def  apply- by blast+ 
himmelma@35172
  1167
himmelma@35172
  1168
definition tagged_division_of (infixr "tagged'_division'_of" 40) where
himmelma@35172
  1169
  "(s tagged_division_of i) \<equiv>
himmelma@35172
  1170
        (s tagged_partial_division_of i) \<and> (\<Union>{k. \<exists>x. (x,k) \<in> s} = i)"
himmelma@35172
  1171
huffman@44167
  1172
lemma tagged_division_of_finite: "s tagged_division_of i \<Longrightarrow> finite s"
himmelma@35172
  1173
  unfolding tagged_division_of_def tagged_partial_division_of_def by auto
himmelma@35172
  1174
himmelma@35172
  1175
lemma tagged_division_of:
himmelma@35172
  1176
 "(s tagged_division_of i) \<longleftrightarrow>
himmelma@35172
  1177
        finite s \<and>
himmelma@35172
  1178
        (\<forall>x k. (x,k) \<in> s
himmelma@35172
  1179
               \<longrightarrow> x \<in> k \<and> k \<subseteq> i \<and> (\<exists>a b. k = {a..b})) \<and>
himmelma@35172
  1180
        (\<forall>x1 k1 x2 k2. (x1,k1) \<in> s \<and> (x2,k2) \<in> s \<and> ~((x1,k1) = (x2,k2))
himmelma@35172
  1181
                       \<longrightarrow> (interior(k1) \<inter> interior(k2) = {})) \<and>
himmelma@35172
  1182
        (\<Union>{k. \<exists>x. (x,k) \<in> s} = i)"
himmelma@35172
  1183
  unfolding tagged_division_of_def tagged_partial_division_of_def by auto
himmelma@35172
  1184
himmelma@35172
  1185
lemma tagged_division_ofI: assumes
himmelma@35172
  1186
  "finite s" "\<And>x k. (x,k) \<in> s \<Longrightarrow> x \<in> k" "\<And>x k. (x,k) \<in> s \<Longrightarrow> k \<subseteq> i"  "\<And>x k. (x,k) \<in> s \<Longrightarrow> \<exists>a b. k = {a..b}"
himmelma@35172
  1187
  "\<And>x1 k1 x2 k2. (x1,k1) \<in> s \<Longrightarrow> (x2,k2) \<in> s \<Longrightarrow> ~((x1,k1) = (x2,k2)) \<Longrightarrow> (interior(k1) \<inter> interior(k2) = {})"
himmelma@35172
  1188
  "(\<Union>{k. \<exists>x. (x,k) \<in> s} = i)"
himmelma@35172
  1189
  shows "s tagged_division_of i"
himmelma@35172
  1190
  unfolding tagged_division_of apply(rule) defer apply rule
himmelma@35172
  1191
  apply(rule allI impI conjI assms)+ apply assumption
himmelma@35172
  1192
  apply(rule, rule assms, assumption) apply(rule assms, assumption)
himmelma@35172
  1193
  using assms(1,5-) apply- by blast+
himmelma@35172
  1194
himmelma@35172
  1195
lemma tagged_division_ofD[dest]: assumes "s tagged_division_of i"
himmelma@35172
  1196
  shows "finite s" "\<And>x k. (x,k) \<in> s \<Longrightarrow> x \<in> k" "\<And>x k. (x,k) \<in> s \<Longrightarrow> k \<subseteq> i"  "\<And>x k. (x,k) \<in> s \<Longrightarrow> \<exists>a b. k = {a..b}"
himmelma@35172
  1197
  "\<And>x1 k1 x2 k2. (x1,k1) \<in> s \<Longrightarrow> (x2,k2) \<in> s \<Longrightarrow> ~((x1,k1) = (x2,k2)) \<Longrightarrow> (interior(k1) \<inter> interior(k2) = {})"
himmelma@35172
  1198
  "(\<Union>{k. \<exists>x. (x,k) \<in> s} = i)" using assms unfolding tagged_division_of apply- by blast+
himmelma@35172
  1199
himmelma@35172
  1200
lemma division_of_tagged_division: assumes"s tagged_division_of i"  shows "(snd ` s) division_of i"
himmelma@35172
  1201
proof(rule division_ofI) note assm=tagged_division_ofD[OF assms]
himmelma@35172
  1202
  show "\<Union>snd ` s = i" "finite (snd ` s)" using assm by auto
himmelma@35172
  1203
  fix k assume k:"k \<in> snd ` s" then obtain xk where xk:"(xk, k) \<in> s" by auto
nipkow@44890
  1204
  thus  "k \<subseteq> i" "k \<noteq> {}" "\<exists>a b. k = {a..b}" using assm apply- by fastforce+
himmelma@35172
  1205
  fix k' assume k':"k' \<in> snd ` s" "k \<noteq> k'" from this(1) obtain xk' where xk':"(xk', k') \<in> s" by auto
himmelma@35172
  1206
  thus "interior k \<inter> interior k' = {}" apply-apply(rule assm(5)) apply(rule xk xk')+ using k' by auto
himmelma@35172
  1207
qed
himmelma@35172
  1208
himmelma@35172
  1209
lemma partial_division_of_tagged_division: assumes "s tagged_partial_division_of i"
himmelma@35172
  1210
  shows "(snd ` s) division_of \<Union>(snd ` s)"
himmelma@35172
  1211
proof(rule division_ofI) note assm=tagged_partial_division_ofD[OF assms]
himmelma@35172
  1212
  show "finite (snd ` s)" "\<Union>snd ` s = \<Union>snd ` s" using assm by auto
himmelma@35172
  1213
  fix k assume k:"k \<in> snd ` s" then obtain xk where xk:"(xk, k) \<in> s" by auto
himmelma@35172
  1214
  thus "k\<noteq>{}" "\<exists>a b. k = {a..b}" "k \<subseteq> \<Union>snd ` s" using assm by auto
himmelma@35172
  1215
  fix k' assume k':"k' \<in> snd ` s" "k \<noteq> k'" from this(1) obtain xk' where xk':"(xk', k') \<in> s" by auto
himmelma@35172
  1216
  thus "interior k \<inter> interior k' = {}" apply-apply(rule assm(5)) apply(rule xk xk')+ using k' by auto
himmelma@35172
  1217
qed
himmelma@35172
  1218
himmelma@35172
  1219
lemma tagged_partial_division_subset: assumes "s tagged_partial_division_of i" "t \<subseteq> s"
himmelma@35172
  1220
  shows "t tagged_partial_division_of i"
himmelma@35172
  1221
  using assms unfolding tagged_partial_division_of_def using finite_subset[OF assms(2)] by blast
himmelma@35172
  1222
hoelzl@37489
  1223
lemma setsum_over_tagged_division_lemma: fixes d::"('m::ordered_euclidean_space) set \<Rightarrow> 'a::real_normed_vector"
himmelma@35172
  1224
  assumes "p tagged_division_of i" "\<And>u v. {u..v} \<noteq> {} \<Longrightarrow> content {u..v} = 0 \<Longrightarrow> d {u..v} = 0"
himmelma@35172
  1225
  shows "setsum (\<lambda>(x,k). d k) p = setsum d (snd ` p)"
himmelma@35172
  1226
proof- note assm=tagged_division_ofD[OF assms(1)]
himmelma@35172
  1227
  have *:"(\<lambda>(x,k). d k) = d \<circ> snd" unfolding o_def apply(rule ext) by auto
himmelma@35172
  1228
  show ?thesis unfolding * apply(subst eq_commute) proof(rule setsum_reindex_nonzero)
himmelma@35172
  1229
    show "finite p" using assm by auto
himmelma@35172
  1230
    fix x y assume as:"x\<in>p" "y\<in>p" "x\<noteq>y" "snd x = snd y" 
himmelma@35172
  1231
    obtain a b where ab:"snd x = {a..b}" using assm(4)[of "fst x" "snd x"] as(1) by auto
himmelma@35172
  1232
    have "(fst x, snd y) \<in> p" "(fst x, snd y) \<noteq> y" unfolding as(4)[THEN sym] using as(1-3) by auto
himmelma@35172
  1233
    hence "interior (snd x) \<inter> interior (snd y) = {}" apply-apply(rule assm(5)[of "fst x" _ "fst y"]) using as by auto 
himmelma@35172
  1234
    hence "content {a..b} = 0" unfolding as(4)[THEN sym] ab content_eq_0_interior by auto
himmelma@35172
  1235
    hence "d {a..b} = 0" apply-apply(rule assms(2)) using assm(2)[of "fst x" "snd x"] as(1) unfolding ab[THEN sym] by auto
himmelma@35172
  1236
    thus "d (snd x) = 0" unfolding ab by auto qed qed
himmelma@35172
  1237
himmelma@35172
  1238
lemma tag_in_interval: "p tagged_division_of i \<Longrightarrow> (x,k) \<in> p \<Longrightarrow> x \<in> i" by auto
himmelma@35172
  1239
himmelma@35172
  1240
lemma tagged_division_of_empty: "{} tagged_division_of {}"
himmelma@35172
  1241
  unfolding tagged_division_of by auto
himmelma@35172
  1242
himmelma@35172
  1243
lemma tagged_partial_division_of_trivial[simp]:
himmelma@35172
  1244
 "p tagged_partial_division_of {} \<longleftrightarrow> p = {}"
himmelma@35172
  1245
  unfolding tagged_partial_division_of_def by auto
himmelma@35172
  1246
himmelma@35172
  1247
lemma tagged_division_of_trivial[simp]:
himmelma@35172
  1248
 "p tagged_division_of {} \<longleftrightarrow> p = {}"
himmelma@35172
  1249
  unfolding tagged_division_of by auto
himmelma@35172
  1250
himmelma@35172
  1251
lemma tagged_division_of_self:
himmelma@35172
  1252
 "x \<in> {a..b} \<Longrightarrow> {(x,{a..b})} tagged_division_of {a..b}"
himmelma@35172
  1253
  apply(rule tagged_division_ofI) by auto
himmelma@35172
  1254
himmelma@35172
  1255
lemma tagged_division_union:
himmelma@35172
  1256
  assumes "p1 tagged_division_of s1"  "p2 tagged_division_of s2" "interior s1 \<inter> interior s2 = {}"
himmelma@35172
  1257
  shows "(p1 \<union> p2) tagged_division_of (s1 \<union> s2)"
himmelma@35172
  1258
proof(rule tagged_division_ofI) note p1=tagged_division_ofD[OF assms(1)] and p2=tagged_division_ofD[OF assms(2)]
himmelma@35172
  1259
  show "finite (p1 \<union> p2)" using p1(1) p2(1) by auto
himmelma@35172
  1260
  show "\<Union>{k. \<exists>x. (x, k) \<in> p1 \<union> p2} = s1 \<union> s2" using p1(6) p2(6) by blast
himmelma@35172
  1261
  fix x k assume xk:"(x,k)\<in>p1\<union>p2" show "x\<in>k" "\<exists>a b. k = {a..b}" using xk p1(2,4) p2(2,4) by auto
himmelma@35172
  1262
  show "k\<subseteq>s1\<union>s2" using xk p1(3) p2(3) by blast
himmelma@35172
  1263
  fix x' k' assume xk':"(x',k')\<in>p1\<union>p2" "(x,k) \<noteq> (x',k')"
huffman@44522
  1264
  have *:"\<And>a b. a\<subseteq> s1 \<Longrightarrow> b\<subseteq> s2 \<Longrightarrow> interior a \<inter> interior b = {}" using assms(3) interior_mono by blast
himmelma@35172
  1265
  show "interior k \<inter> interior k' = {}" apply(cases "(x,k)\<in>p1", case_tac[!] "(x',k')\<in>p1")
himmelma@35172
  1266
    apply(rule p1(5)) prefer 4 apply(rule *) prefer 6 apply(subst Int_commute,rule *) prefer 8 apply(rule p2(5))
himmelma@35172
  1267
    using p1(3) p2(3) using xk xk' by auto qed 
himmelma@35172
  1268
himmelma@35172
  1269
lemma tagged_division_unions:
himmelma@35172
  1270
  assumes "finite iset" "\<forall>i\<in>iset. (pfn(i) tagged_division_of i)"
himmelma@35172
  1271
  "\<forall>i1 \<in> iset. \<forall>i2 \<in> iset. ~(i1 = i2) \<longrightarrow> (interior(i1) \<inter> interior(i2) = {})"
himmelma@35172
  1272
  shows "\<Union>(pfn ` iset) tagged_division_of (\<Union>iset)"
himmelma@35172
  1273
proof(rule tagged_division_ofI)
himmelma@35172
  1274
  note assm = tagged_division_ofD[OF assms(2)[rule_format]]
himmelma@35172
  1275
  show "finite (\<Union>pfn ` iset)" apply(rule finite_Union) using assms by auto
himmelma@35172
  1276
  have "\<Union>{k. \<exists>x. (x, k) \<in> \<Union>pfn ` iset} = \<Union>(\<lambda>i. \<Union>{k. \<exists>x. (x, k) \<in> pfn i}) ` iset" by blast 
himmelma@35172
  1277
  also have "\<dots> = \<Union>iset" using assm(6) by auto
himmelma@35172
  1278
  finally show "\<Union>{k. \<exists>x. (x, k) \<in> \<Union>pfn ` iset} = \<Union>iset" . 
himmelma@35172
  1279
  fix x k assume xk:"(x,k)\<in>\<Union>pfn ` iset" then obtain i where i:"i \<in> iset" "(x, k) \<in> pfn i" by auto
himmelma@35172
  1280
  show "x\<in>k" "\<exists>a b. k = {a..b}" "k \<subseteq> \<Union>iset" using assm(2-4)[OF i] using i(1) by auto
himmelma@35172
  1281
  fix x' k' assume xk':"(x',k')\<in>\<Union>pfn ` iset" "(x, k) \<noteq> (x', k')" then obtain i' where i':"i' \<in> iset" "(x', k') \<in> pfn i'" by auto
himmelma@35172
  1282
  have *:"\<And>a b. i\<noteq>i' \<Longrightarrow> a\<subseteq> i \<Longrightarrow> b\<subseteq> i' \<Longrightarrow> interior a \<inter> interior b = {}" using i(1) i'(1)
huffman@44522
  1283
    using assms(3)[rule_format] interior_mono by blast
himmelma@35172
  1284
  show "interior k \<inter> interior k' = {}" apply(cases "i=i'")
himmelma@35172
  1285
    using assm(5)[OF i _ xk'(2)]  i'(2) using assm(3)[OF i] assm(3)[OF i'] defer apply-apply(rule *) by auto
himmelma@35172
  1286
qed
himmelma@35172
  1287
himmelma@35172
  1288
lemma tagged_partial_division_of_union_self:
himmelma@35172
  1289
  assumes "p tagged_partial_division_of s" shows "p tagged_division_of (\<Union>(snd ` p))"
himmelma@35172
  1290
  apply(rule tagged_division_ofI) using tagged_partial_division_ofD[OF assms] by auto
himmelma@35172
  1291
himmelma@35172
  1292
lemma tagged_division_of_union_self: assumes "p tagged_division_of s"
himmelma@35172
  1293
  shows "p tagged_division_of (\<Union>(snd ` p))"
himmelma@35172
  1294
  apply(rule tagged_division_ofI) using tagged_division_ofD[OF assms] by auto
himmelma@35172
  1295
himmelma@35172
  1296
subsection {* Fine-ness of a partition w.r.t. a gauge. *}
himmelma@35172
  1297
himmelma@35172
  1298
definition fine (infixr "fine" 46) where
himmelma@35172
  1299
  "d fine s \<longleftrightarrow> (\<forall>(x,k) \<in> s. k \<subseteq> d(x))"
himmelma@35172
  1300
himmelma@35172
  1301
lemma fineI: assumes "\<And>x k. (x,k) \<in> s \<Longrightarrow> k \<subseteq> d x"
himmelma@35172
  1302
  shows "d fine s" using assms unfolding fine_def by auto
himmelma@35172
  1303
himmelma@35172
  1304
lemma fineD[dest]: assumes "d fine s"
himmelma@35172
  1305
  shows "\<And>x k. (x,k) \<in> s \<Longrightarrow> k \<subseteq> d x" using assms unfolding fine_def by auto
himmelma@35172
  1306
himmelma@35172
  1307
lemma fine_inter: "(\<lambda>x. d1 x \<inter> d2 x) fine p \<longleftrightarrow> d1 fine p \<and> d2 fine p"
himmelma@35172
  1308
  unfolding fine_def by auto
himmelma@35172
  1309
himmelma@35172
  1310
lemma fine_inters:
himmelma@35172
  1311
 "(\<lambda>x. \<Inter> {f d x | d.  d \<in> s}) fine p \<longleftrightarrow> (\<forall>d\<in>s. (f d) fine p)"
himmelma@35172
  1312
  unfolding fine_def by blast
himmelma@35172
  1313
himmelma@35172
  1314
lemma fine_union:
himmelma@35172
  1315
  "d fine p1 \<Longrightarrow> d fine p2 \<Longrightarrow> d fine (p1 \<union> p2)"
himmelma@35172
  1316
  unfolding fine_def by blast
himmelma@35172
  1317
himmelma@35172
  1318
lemma fine_unions:"(\<And>p. p \<in> ps \<Longrightarrow> d fine p) \<Longrightarrow> d fine (\<Union>ps)"
himmelma@35172
  1319
  unfolding fine_def by auto
himmelma@35172
  1320
himmelma@35172
  1321
lemma fine_subset:  "p \<subseteq> q \<Longrightarrow> d fine q \<Longrightarrow> d fine p"
himmelma@35172
  1322
  unfolding fine_def by blast
himmelma@35172
  1323
himmelma@35172
  1324
subsection {* Gauge integral. Define on compact intervals first, then use a limit. *}
himmelma@35172
  1325
himmelma@35172
  1326
definition has_integral_compact_interval (infixr "has'_integral'_compact'_interval" 46) where
himmelma@35172
  1327
  "(f has_integral_compact_interval y) i \<equiv>
himmelma@35172
  1328
        (\<forall>e>0. \<exists>d. gauge d \<and>
himmelma@35172
  1329
          (\<forall>p. p tagged_division_of i \<and> d fine p
himmelma@35172
  1330
                        \<longrightarrow> norm(setsum (\<lambda>(x,k). content k *\<^sub>R f x) p - y) < e))"
himmelma@35172
  1331
himmelma@35172
  1332
definition has_integral (infixr "has'_integral" 46) where 
hoelzl@37489
  1333
"((f::('n::ordered_euclidean_space \<Rightarrow> 'b::real_normed_vector)) has_integral y) i \<equiv>
himmelma@35172
  1334
        if (\<exists>a b. i = {a..b}) then (f has_integral_compact_interval y) i
himmelma@35172
  1335
        else (\<forall>e>0. \<exists>B>0. \<forall>a b. ball 0 B \<subseteq> {a..b}
himmelma@35172
  1336
              \<longrightarrow> (\<exists>z. ((\<lambda>x. if x \<in> i then f x else 0) has_integral_compact_interval z) {a..b} \<and>
himmelma@35172
  1337
                                       norm(z - y) < e))"
himmelma@35172
  1338
himmelma@35172
  1339
lemma has_integral:
himmelma@35172
  1340
 "(f has_integral y) ({a..b}) \<longleftrightarrow>
himmelma@35172
  1341
        (\<forall>e>0. \<exists>d. gauge d \<and> (\<forall>p. p tagged_division_of {a..b} \<and> d fine p
himmelma@35172
  1342
                        \<longrightarrow> norm(setsum (\<lambda>(x,k). content(k) *\<^sub>R f x) p - y) < e))"
himmelma@35172
  1343
  unfolding has_integral_def has_integral_compact_interval_def by auto
himmelma@35172
  1344
himmelma@35172
  1345
lemma has_integralD[dest]: assumes
himmelma@35172
  1346
 "(f has_integral y) ({a..b})" "e>0"
himmelma@35172
  1347
  obtains d where "gauge d" "\<And>p. p tagged_division_of {a..b} \<Longrightarrow> d fine p
himmelma@35172
  1348
                        \<Longrightarrow> norm(setsum (\<lambda>(x,k). content(k) *\<^sub>R f(x)) p - y) < e"
himmelma@35172
  1349
  using assms unfolding has_integral by auto
himmelma@35172
  1350
himmelma@35172
  1351
lemma has_integral_alt:
himmelma@35172
  1352
 "(f has_integral y) i \<longleftrightarrow>
himmelma@35172
  1353
      (if (\<exists>a b. i = {a..b}) then (f has_integral y) i
himmelma@35172
  1354
       else (\<forall>e>0. \<exists>B>0. \<forall>a b. ball 0 B \<subseteq> {a..b}
himmelma@35172
  1355
                               \<longrightarrow> (\<exists>z. ((\<lambda>x. if x \<in> i then f(x) else 0)
himmelma@35172
  1356
                                        has_integral z) ({a..b}) \<and>
himmelma@35172
  1357
                                       norm(z - y) < e)))"
himmelma@35172
  1358
  unfolding has_integral unfolding has_integral_compact_interval_def has_integral_def by auto
himmelma@35172
  1359
himmelma@35172
  1360
lemma has_integral_altD:
himmelma@35172
  1361
  assumes "(f has_integral y) i" "\<not> (\<exists>a b. i = {a..b})" "e>0"
himmelma@35172
  1362
  obtains B where "B>0" "\<forall>a b. ball 0 B \<subseteq> {a..b}\<longrightarrow> (\<exists>z. ((\<lambda>x. if x \<in> i then f(x) else 0) has_integral z) ({a..b}) \<and> norm(z - y) < e)"
himmelma@35172
  1363
  using assms unfolding has_integral unfolding has_integral_compact_interval_def has_integral_def by auto
himmelma@35172
  1364
himmelma@35172
  1365
definition integrable_on (infixr "integrable'_on" 46) where
himmelma@35172
  1366
  "(f integrable_on i) \<equiv> \<exists>y. (f has_integral y) i"
himmelma@35172
  1367
himmelma@35172
  1368
definition "integral i f \<equiv> SOME y. (f has_integral y) i"
himmelma@35172
  1369
himmelma@35172
  1370
lemma integrable_integral[dest]:
himmelma@35172
  1371
 "f integrable_on i \<Longrightarrow> (f has_integral (integral i f)) i"
himmelma@35172
  1372
  unfolding integrable_on_def integral_def by(rule someI_ex)
himmelma@35172
  1373
himmelma@35172
  1374
lemma has_integral_integrable[intro]: "(f has_integral i) s \<Longrightarrow> f integrable_on s"
himmelma@35172
  1375
  unfolding integrable_on_def by auto
himmelma@35172
  1376
himmelma@35172
  1377
lemma has_integral_integral:"f integrable_on s \<longleftrightarrow> (f has_integral (integral s f)) s"
himmelma@35172
  1378
  by auto
himmelma@35172
  1379
himmelma@35172
  1380
lemma setsum_content_null:
himmelma@35172
  1381
  assumes "content({a..b}) = 0" "p tagged_division_of {a..b}"
himmelma@35172
  1382
  shows "setsum (\<lambda>(x,k). content k *\<^sub>R f x) p = (0::'a::real_normed_vector)"
himmelma@35172
  1383
proof(rule setsum_0',rule) fix y assume y:"y\<in>p"
himmelma@35172
  1384
  obtain x k where xk:"y = (x,k)" using surj_pair[of y] by blast
himmelma@35172
  1385
  note assm = tagged_division_ofD(3-4)[OF assms(2) y[unfolded xk]]
himmelma@35172
  1386
  from this(2) guess c .. then guess d .. note c_d=this
himmelma@35172
  1387
  have "(\<lambda>(x, k). content k *\<^sub>R f x) y = content k *\<^sub>R f x" unfolding xk by auto
himmelma@35172
  1388
  also have "\<dots> = 0" using content_subset[OF assm(1)[unfolded c_d]] content_pos_le[of c d]
himmelma@35172
  1389
    unfolding assms(1) c_d by auto
himmelma@35172
  1390
  finally show "(\<lambda>(x, k). content k *\<^sub>R f x) y = 0" .
himmelma@35172
  1391
qed
himmelma@35172
  1392
himmelma@35172
  1393
subsection {* Some basic combining lemmas. *}
himmelma@35172
  1394
himmelma@35172
  1395
lemma tagged_division_unions_exists:
himmelma@35172
  1396
  assumes "finite iset" "\<forall>i \<in> iset. \<exists>p. p tagged_division_of i \<and> d fine p"
himmelma@35172
  1397
  "\<forall>i1\<in>iset. \<forall>i2\<in>iset. ~(i1 = i2) \<longrightarrow> (interior(i1) \<inter> interior(i2) = {})" "(\<Union>iset = i)"
himmelma@35172
  1398
   obtains p where "p tagged_division_of i" "d fine p"
himmelma@35172
  1399
proof- guess pfn using bchoice[OF assms(2)] .. note pfn = conjunctD2[OF this[rule_format]]
himmelma@35172
  1400
  show thesis apply(rule_tac p="\<Union>(pfn ` iset)" in that) unfolding assms(4)[THEN sym]
himmelma@35172
  1401
    apply(rule tagged_division_unions[OF assms(1) _ assms(3)]) defer 
himmelma@35172
  1402
    apply(rule fine_unions) using pfn by auto
himmelma@35172
  1403
qed
himmelma@35172
  1404
himmelma@35172
  1405
subsection {* The set we're concerned with must be closed. *}
himmelma@35172
  1406
hoelzl@37489
  1407
lemma division_of_closed: "s division_of i \<Longrightarrow> closed (i::('n::ordered_euclidean_space) set)"
nipkow@44890
  1408
  unfolding division_of_def by fastforce
himmelma@35172
  1409
himmelma@35172
  1410
subsection {* General bisection principle for intervals; might be useful elsewhere. *}
himmelma@35172
  1411
hoelzl@37489
  1412
lemma interval_bisection_step:  fixes type::"'a::ordered_euclidean_space"
hoelzl@37489
  1413
  assumes "P {}" "(\<forall>s t. P s \<and> P t \<and> interior(s) \<inter> interior(t) = {} \<longrightarrow> P(s \<union> t))" "~(P {a..b::'a})"
himmelma@35172
  1414
  obtains c d where "~(P{c..d})"
hoelzl@37489
  1415
  "\<forall>i<DIM('a). a$$i \<le> c$$i \<and> c$$i \<le> d$$i \<and> d$$i \<le> b$$i \<and> 2 * (d$$i - c$$i) \<le> b$$i - a$$i"
himmelma@35172
  1416
proof- have "{a..b} \<noteq> {}" using assms(1,3) by auto
himmelma@35172
  1417
  note ab=this[unfolded interval_eq_empty not_ex not_less]
himmelma@35172
  1418
  { fix f have "finite f \<Longrightarrow>
himmelma@35172
  1419
        (\<forall>s\<in>f. P s) \<Longrightarrow>
himmelma@35172
  1420
        (\<forall>s\<in>f. \<exists>a b. s = {a..b}) \<Longrightarrow>
himmelma@35172
  1421
        (\<forall>s\<in>f.\<forall>t\<in>f. ~(s = t) \<longrightarrow> interior(s) \<inter> interior(t) = {}) \<Longrightarrow> P(\<Union>f)"
himmelma@35172
  1422
    proof(induct f rule:finite_induct)
himmelma@35172
  1423
      case empty show ?case using assms(1) by auto
himmelma@35172
  1424
    next case (insert x f) show ?case unfolding Union_insert apply(rule assms(2)[rule_format])
himmelma@35172
  1425
        apply rule defer apply rule defer apply(rule inter_interior_unions_intervals)
himmelma@35172
  1426
        using insert by auto
himmelma@35172
  1427
    qed } note * = this
hoelzl@37489
  1428
  let ?A = "{{c..d} | c d::'a. \<forall>i<DIM('a). (c$$i = a$$i) \<and> (d$$i = (a$$i + b$$i) / 2) \<or> (c$$i = (a$$i + b$$i) / 2) \<and> (d$$i = b$$i)}"
hoelzl@37489
  1429
  let ?PP = "\<lambda>c d. \<forall>i<DIM('a). a$$i \<le> c$$i \<and> c$$i \<le> d$$i \<and> d$$i \<le> b$$i \<and> 2 * (d$$i - c$$i) \<le> b$$i - a$$i"
himmelma@35172
  1430
  { presume "\<forall>c d. ?PP c d \<longrightarrow> P {c..d} \<Longrightarrow> False"
himmelma@35172
  1431
    thus thesis unfolding atomize_not not_all apply-apply(erule exE)+ apply(rule_tac c=x and d=xa in that) by auto }
himmelma@35172
  1432
  assume as:"\<forall>c d. ?PP c d \<longrightarrow> P {c..d}"
himmelma@35172
  1433
  have "P (\<Union> ?A)" proof(rule *, rule_tac[2-] ballI, rule_tac[4] ballI, rule_tac[4] impI) 
hoelzl@37489
  1434
    let ?B = "(\<lambda>s.{(\<chi>\<chi> i. if i \<in> s then a$$i else (a$$i + b$$i) / 2)::'a ..
hoelzl@37489
  1435
      (\<chi>\<chi> i. if i \<in> s then (a$$i + b$$i) / 2 else b$$i)}) ` {s. s \<subseteq> {..<DIM('a)}}"
himmelma@35172
  1436
    have "?A \<subseteq> ?B" proof case goal1
himmelma@35172
  1437
      then guess c unfolding mem_Collect_eq .. then guess d apply- by(erule exE,(erule conjE)+) note c_d=this[rule_format]
himmelma@35172
  1438
      have *:"\<And>a b c d. a = c \<Longrightarrow> b = d \<Longrightarrow> {a..b} = {c..d}" by auto
hoelzl@37489
  1439
      show "x\<in>?B" unfolding image_iff apply(rule_tac x="{i. i<DIM('a) \<and> c$$i = a$$i}" in bexI)
hoelzl@37489
  1440
        unfolding c_d apply(rule * ) unfolding euclidean_eq[where 'a='a] apply safe unfolding euclidean_lambda_beta' mem_Collect_eq
hoelzl@37489
  1441
      proof- fix i assume "i<DIM('a)" thus " c $$ i = (if i < DIM('a) \<and> c $$ i = a $$ i then a $$ i else (a $$ i + b $$ i) / 2)"
hoelzl@37489
  1442
          "d $$ i = (if i < DIM('a) \<and> c $$ i = a $$ i then (a $$ i + b $$ i) / 2 else b $$ i)"
himmelma@35172
  1443
          using c_d(2)[of i] ab[THEN spec[where x=i]] by(auto simp add:field_simps)
hoelzl@37489
  1444
      qed qed
hoelzl@37489
  1445
    thus "finite ?A" apply(rule finite_subset) by auto
himmelma@35172
  1446
    fix s assume "s\<in>?A" then guess c unfolding mem_Collect_eq .. then guess d apply- by(erule exE,(erule conjE)+)
himmelma@35172
  1447
    note c_d=this[rule_format]
hoelzl@37489
  1448
    show "P s" unfolding c_d apply(rule as[rule_format]) proof- case goal1 thus ?case 
himmelma@35172
  1449
        using c_d(2)[of i] using ab[THEN spec[where x=i]] by auto qed
himmelma@35172
  1450
    show "\<exists>a b. s = {a..b}" unfolding c_d by auto
himmelma@35172
  1451
    fix t assume "t\<in>?A" then guess e unfolding mem_Collect_eq .. then guess f apply- by(erule exE,(erule conjE)+)
himmelma@35172
  1452
    note e_f=this[rule_format]
himmelma@35172
  1453
    assume "s \<noteq> t" hence "\<not> (c = e \<and> d = f)" unfolding c_d e_f by auto
hoelzl@37489
  1454
    then obtain i where "c$$i \<noteq> e$$i \<or> d$$i \<noteq> f$$i" and i':"i<DIM('a)" unfolding de_Morgan_conj euclidean_eq[where 'a='a] by auto
hoelzl@37489
  1455
    hence i:"c$$i \<noteq> e$$i" "d$$i \<noteq> f$$i" apply- apply(erule_tac[!] disjE)
nipkow@44890
  1456
    proof- assume "c$$i \<noteq> e$$i" thus "d$$i \<noteq> f$$i" using c_d(2)[of i] e_f(2)[of i] by fastforce
nipkow@44890
  1457
    next   assume "d$$i \<noteq> f$$i" thus "c$$i \<noteq> e$$i" using c_d(2)[of i] e_f(2)[of i] by fastforce
himmelma@35172
  1458
    qed have *:"\<And>s t. (\<And>a. a\<in>s \<Longrightarrow> a\<in>t \<Longrightarrow> False) \<Longrightarrow> s \<inter> t = {}" by auto
himmelma@35172
  1459
    show "interior s \<inter> interior t = {}" unfolding e_f c_d interior_closed_interval proof(rule *)
himmelma@35172
  1460
      fix x assume "x\<in>{c<..<d}" "x\<in>{e<..<f}"
hoelzl@37489
  1461
      hence x:"c$$i < d$$i" "e$$i < f$$i" "c$$i < f$$i" "e$$i < d$$i" unfolding mem_interval using i'
hoelzl@37489
  1462
        apply-apply(erule_tac[!] x=i in allE)+ by auto
hoelzl@37489
  1463
      show False using c_d(2)[OF i'] apply- apply(erule_tac disjE)
hoelzl@37489
  1464
      proof(erule_tac[!] conjE) assume as:"c $$ i = a $$ i" "d $$ i = (a $$ i + b $$ i) / 2"
nipkow@44890
  1465
        show False using e_f(2)[of i] and i x unfolding as by(fastforce simp add:field_simps)
hoelzl@37489
  1466
      next assume as:"c $$ i = (a $$ i + b $$ i) / 2" "d $$ i = b $$ i"
nipkow@44890
  1467
        show False using e_f(2)[of i] and i x unfolding as by(fastforce simp add:field_simps)
himmelma@35172
  1468
      qed qed qed
nipkow@39302
  1469
  also have "\<Union> ?A = {a..b}" proof(rule set_eqI,rule)
himmelma@35172
  1470
    fix x assume "x\<in>\<Union>?A" then guess Y unfolding Union_iff ..
himmelma@35172
  1471
    from this(1) guess c unfolding mem_Collect_eq .. then guess d ..
himmelma@35172
  1472
    note c_d = this[THEN conjunct2,rule_format] `x\<in>Y`[unfolded this[THEN conjunct1]]
hoelzl@37489
  1473
    show "x\<in>{a..b}" unfolding mem_interval proof safe
hoelzl@37489
  1474
      fix i assume "i<DIM('a)" thus "a $$ i \<le> x $$ i" "x $$ i \<le> b $$ i"
himmelma@35172
  1475
        using c_d(1)[of i] c_d(2)[unfolded mem_interval,THEN spec[where x=i]] by auto qed
himmelma@35172
  1476
  next fix x assume x:"x\<in>{a..b}"
hoelzl@37489
  1477
    have "\<forall>i<DIM('a). \<exists>c d. (c = a$$i \<and> d = (a$$i + b$$i) / 2 \<or> c = (a$$i + b$$i) / 2 \<and> d = b$$i) \<and> c\<le>x$$i \<and> x$$i \<le> d"
hoelzl@37489
  1478
      (is "\<forall>i<DIM('a). \<exists>c d. ?P i c d") unfolding mem_interval proof(rule,rule) fix i
hoelzl@37489
  1479
      have "?P i (a$$i) ((a $$ i + b $$ i) / 2) \<or> ?P i ((a $$ i + b $$ i) / 2) (b$$i)"
himmelma@35172
  1480
        using x[unfolded mem_interval,THEN spec[where x=i]] by auto thus "\<exists>c d. ?P i c d" by blast
hoelzl@37489
  1481
    qed thus "x\<in>\<Union>?A" unfolding Union_iff unfolding lambda_skolem' unfolding Bex_def mem_Collect_eq
himmelma@35172
  1482
      apply-apply(erule exE)+ apply(rule_tac x="{xa..xaa}" in exI) unfolding mem_interval by auto
himmelma@35172
  1483
  qed finally show False using assms by auto qed
himmelma@35172
  1484
hoelzl@37489
  1485
lemma interval_bisection: fixes type::"'a::ordered_euclidean_space"
hoelzl@37489
  1486
  assumes "P {}" "(\<forall>s t. P s \<and> P t \<and> interior(s) \<inter> interior(t) = {} \<longrightarrow> P(s \<union> t))" "\<not> P {a..b::'a}"
himmelma@35172
  1487
  obtains x where "x \<in> {a..b}" "\<forall>e>0. \<exists>c d. x \<in> {c..d} \<and> {c..d} \<subseteq> ball x e \<and> {c..d} \<subseteq> {a..b} \<and> ~P({c..d})"
himmelma@35172
  1488
proof-
hoelzl@37489
  1489
  have "\<forall>x. \<exists>y. \<not> P {fst x..snd x} \<longrightarrow> (\<not> P {fst y..snd y} \<and>
hoelzl@37489
  1490
    (\<forall>i<DIM('a). fst x$$i \<le> fst y$$i \<and> fst y$$i \<le> snd y$$i \<and> snd y$$i \<le> snd x$$i \<and>
hoelzl@37489
  1491
                           2 * (snd y$$i - fst y$$i) \<le> snd x$$i - fst x$$i))" proof case goal1 thus ?case proof-
himmelma@35172
  1492
      presume "\<not> P {fst x..snd x} \<Longrightarrow> ?thesis"
himmelma@35172
  1493
      thus ?thesis apply(cases "P {fst x..snd x}") by auto
himmelma@35172
  1494
    next assume as:"\<not> P {fst x..snd x}" from interval_bisection_step[of P, OF assms(1-2) as] guess c d . 
himmelma@35172
  1495
      thus ?thesis apply- apply(rule_tac x="(c,d)" in exI) by auto
himmelma@35172
  1496
    qed qed then guess f apply-apply(drule choice) by(erule exE) note f=this
himmelma@35172
  1497
  def AB \<equiv> "\<lambda>n. (f ^^ n) (a,b)" def A \<equiv> "\<lambda>n. fst(AB n)" and B \<equiv> "\<lambda>n. snd(AB n)" note ab_def = this AB_def
himmelma@35172
  1498
  have "A 0 = a" "B 0 = b" "\<And>n. \<not> P {A(Suc n)..B(Suc n)} \<and>
hoelzl@37489
  1499
    (\<forall>i<DIM('a). A(n)$$i \<le> A(Suc n)$$i \<and> A(Suc n)$$i \<le> B(Suc n)$$i \<and> B(Suc n)$$i \<le> B(n)$$i \<and> 
hoelzl@37489
  1500
    2 * (B(Suc n)$$i - A(Suc n)$$i) \<le> B(n)$$i - A(n)$$i)" (is "\<And>n. ?P n")
himmelma@35172
  1501
  proof- show "A 0 = a" "B 0 = b" unfolding ab_def by auto
himmelma@35172
  1502
    case goal3 note S = ab_def funpow.simps o_def id_apply show ?case
himmelma@35172
  1503
    proof(induct n) case 0 thus ?case unfolding S apply(rule f[rule_format]) using assms(3) by auto
himmelma@35172
  1504
    next case (Suc n) show ?case unfolding S apply(rule f[rule_format]) using Suc unfolding S by auto
himmelma@35172
  1505
    qed qed note AB = this(1-2) conjunctD2[OF this(3),rule_format]
himmelma@35172
  1506
himmelma@35172
  1507
  have interv:"\<And>e. 0 < e \<Longrightarrow> \<exists>n. \<forall>x\<in>{A n..B n}. \<forall>y\<in>{A n..B n}. dist x y < e"
hoelzl@37489
  1508
  proof- case goal1 guess n using real_arch_pow2[of "(setsum (\<lambda>i. b$$i - a$$i) {..<DIM('a)}) / e"] .. note n=this
himmelma@35172
  1509
    show ?case apply(rule_tac x=n in exI) proof(rule,rule)
himmelma@35172
  1510
      fix x y assume xy:"x\<in>{A n..B n}" "y\<in>{A n..B n}"
hoelzl@37489
  1511
      have "dist x y \<le> setsum (\<lambda>i. abs((x - y)$$i)) {..<DIM('a)}" unfolding dist_norm by(rule norm_le_l1)
hoelzl@37489
  1512
      also have "\<dots> \<le> setsum (\<lambda>i. B n$$i - A n$$i) {..<DIM('a)}"
hoelzl@37489
  1513
      proof(rule setsum_mono) fix i show "\<bar>(x - y) $$ i\<bar> \<le> B n $$ i - A n $$ i"
hoelzl@37489
  1514
          using xy[unfolded mem_interval,THEN spec[where x=i]] by auto qed
hoelzl@37489
  1515
      also have "\<dots> \<le> setsum (\<lambda>i. b$$i - a$$i) {..<DIM('a)} / 2^n" unfolding setsum_divide_distrib
himmelma@35172
  1516
      proof(rule setsum_mono) case goal1 thus ?case
himmelma@35172
  1517
        proof(induct n) case 0 thus ?case unfolding AB by auto
hoelzl@37489
  1518
        next case (Suc n) have "B (Suc n) $$ i - A (Suc n) $$ i \<le> (B n $$ i - A n $$ i) / 2"
hoelzl@37489
  1519
            using AB(4)[of i n] using goal1 by auto
hoelzl@37489
  1520
          also have "\<dots> \<le> (b $$ i - a $$ i) / 2 ^ Suc n" using Suc by(auto simp add:field_simps) finally show ?case .
himmelma@35172
  1521
        qed qed
himmelma@35172
  1522
      also have "\<dots> < e" using n using goal1 by(auto simp add:field_simps) finally show "dist x y < e" .
himmelma@35172
  1523
    qed qed
himmelma@35172
  1524
  { fix n m ::nat assume "m \<le> n" then guess d unfolding le_Suc_ex_iff .. note d=this
himmelma@35172
  1525
    have "{A n..B n} \<subseteq> {A m..B m}" unfolding d 
himmelma@35172
  1526
    proof(induct d) case 0 thus ?case by auto
himmelma@35172
  1527
    next case (Suc d) show ?case apply(rule subset_trans[OF _ Suc])
himmelma@35172
  1528
        apply(rule) unfolding mem_interval apply(rule,erule_tac x=i in allE)
hoelzl@37489
  1529
      proof- case goal1 thus ?case using AB(4)[of i "m + d"] by(auto simp add:field_simps)
himmelma@35172
  1530
      qed qed } note ABsubset = this 
himmelma@35172
  1531
  have "\<exists>a. \<forall>n. a\<in>{A n..B n}" apply(rule decreasing_closed_nest[rule_format,OF closed_interval _ ABsubset interv])
himmelma@35172
  1532
  proof- fix n show "{A n..B n} \<noteq> {}" apply(cases "0<n") using AB(3)[of "n - 1"] assms(1,3) AB(1-2) by auto qed auto
himmelma@35172
  1533
  then guess x0 .. note x0=this[rule_format]
himmelma@35172
  1534
  show thesis proof(rule that[rule_format,of x0])
himmelma@35172
  1535
    show "x0\<in>{a..b}" using x0[of 0] unfolding AB .
himmelma@35172
  1536
    fix e assume "0 < (e::real)" from interv[OF this] guess n .. note n=this
himmelma@35172
  1537
    show "\<exists>c d. x0 \<in> {c..d} \<and> {c..d} \<subseteq> ball x0 e \<and> {c..d} \<subseteq> {a..b} \<and> \<not> P {c..d}"
himmelma@35172
  1538
      apply(rule_tac x="A n" in exI,rule_tac x="B n" in exI) apply(rule,rule x0) apply rule defer 
himmelma@35172
  1539
    proof show "\<not> P {A n..B n}" apply(cases "0<n") using AB(3)[of "n - 1"] assms(3) AB(1-2) by auto
himmelma@35172
  1540
      show "{A n..B n} \<subseteq> ball x0 e" using n using x0[of n] by auto
himmelma@35172
  1541
      show "{A n..B n} \<subseteq> {a..b}" unfolding AB(1-2)[symmetric] apply(rule ABsubset) by auto
himmelma@35172
  1542
    qed qed qed 
himmelma@35172
  1543
himmelma@35172
  1544
subsection {* Cousin's lemma. *}
himmelma@35172
  1545
himmelma@35172
  1546
lemma fine_division_exists: assumes "gauge g" 
hoelzl@37489
  1547
  obtains p where "p tagged_division_of {a..b::'a::ordered_euclidean_space}" "g fine p"
himmelma@35172
  1548
proof- presume "\<not> (\<exists>p. p tagged_division_of {a..b} \<and> g fine p) \<Longrightarrow> False"
himmelma@35172
  1549
  then guess p unfolding atomize_not not_not .. thus thesis apply-apply(rule that[of p]) by auto
himmelma@35172
  1550
next assume as:"\<not> (\<exists>p. p tagged_division_of {a..b} \<and> g fine p)"
himmelma@35172
  1551
  guess x apply(rule interval_bisection[of "\<lambda>s. \<exists>p. p tagged_division_of s \<and> g fine p",rule_format,OF _ _ as])
himmelma@35172
  1552
    apply(rule_tac x="{}" in exI) defer apply(erule conjE exE)+
himmelma@35172
  1553
  proof- show "{} tagged_division_of {} \<and> g fine {}" unfolding fine_def by auto
himmelma@35172
  1554
    fix s t p p' assume "p tagged_division_of s" "g fine p" "p' tagged_division_of t" "g fine p'" "interior s \<inter> interior t = {}"
himmelma@35172
  1555
    thus "\<exists>p. p tagged_division_of s \<union> t \<and> g fine p" apply-apply(rule_tac x="p \<union> p'" in exI) apply rule
himmelma@35172
  1556
      apply(rule tagged_division_union) prefer 4 apply(rule fine_union) by auto
himmelma@35172
  1557
  qed note x=this
himmelma@35172
  1558
  obtain e where e:"e>0" "ball x e \<subseteq> g x" using gaugeD[OF assms, of x] unfolding open_contains_ball by auto
himmelma@35172
  1559
  from x(2)[OF e(1)] guess c d apply-apply(erule exE conjE)+ . note c_d = this
himmelma@35172
  1560
  have "g fine {(x, {c..d})}" unfolding fine_def using e using c_d(2) by auto
himmelma@35172
  1561
  thus False using tagged_division_of_self[OF c_d(1)] using c_d by auto qed
himmelma@35172
  1562
himmelma@35172
  1563
subsection {* Basic theorems about integrals. *}
himmelma@35172
  1564
hoelzl@37489
  1565
lemma has_integral_unique: fixes f::"'n::ordered_euclidean_space \<Rightarrow> 'a::real_normed_vector"
himmelma@35172
  1566
  assumes "(f has_integral k1) i" "(f has_integral k2) i" shows "k1 = k2"
himmelma@35172
  1567
proof(rule ccontr) let ?e = "norm(k1 - k2) / 2" assume as:"k1 \<noteq> k2" hence e:"?e > 0" by auto
hoelzl@37489
  1568
  have lem:"\<And>f::'n \<Rightarrow> 'a.  \<And> a b k1 k2.
himmelma@35172
  1569
    (f has_integral k1) ({a..b}) \<Longrightarrow> (f has_integral k2) ({a..b}) \<Longrightarrow> k1 \<noteq> k2 \<Longrightarrow> False"
himmelma@35172
  1570
  proof- case goal1 let ?e = "norm(k1 - k2) / 2" from goal1(3) have e:"?e > 0" by auto
himmelma@35172
  1571
    guess d1 by(rule has_integralD[OF goal1(1) e]) note d1=this
himmelma@35172
  1572
    guess d2 by(rule has_integralD[OF goal1(2) e]) note d2=this
himmelma@35172
  1573
    guess p by(rule fine_division_exists[OF gauge_inter[OF d1(1) d2(1)],of a b]) note p=this
himmelma@35172
  1574
    let ?c = "(\<Sum>(x, k)\<in>p. content k *\<^sub>R f x)" have "norm (k1 - k2) \<le> norm (?c - k2) + norm (?c - k1)"
haftmann@36350
  1575
      using norm_triangle_ineq4[of "k1 - ?c" "k2 - ?c"] by(auto simp add:algebra_simps norm_minus_commute)
himmelma@35172
  1576
    also have "\<dots> < norm (k1 - k2) / 2 + norm (k1 - k2) / 2"
himmelma@35172
  1577
      apply(rule add_strict_mono) apply(rule_tac[!] d2(2) d1(2)) using p unfolding fine_def by auto
himmelma@35172
  1578
    finally show False by auto
himmelma@35172
  1579
  qed { presume "\<not> (\<exists>a b. i = {a..b}) \<Longrightarrow> False"
himmelma@35172
  1580
    thus False apply-apply(cases "\<exists>a b. i = {a..b}")
himmelma@35172
  1581
      using assms by(auto simp add:has_integral intro:lem[OF _ _ as]) }
himmelma@35172
  1582
  assume as:"\<not> (\<exists>a b. i = {a..b})"
himmelma@35172
  1583
  guess B1 by(rule has_integral_altD[OF assms(1) as,OF e]) note B1=this[rule_format]
himmelma@35172
  1584
  guess B2 by(rule has_integral_altD[OF assms(2) as,OF e]) note B2=this[rule_format]
hoelzl@37489
  1585
  have "\<exists>a b::'n. ball 0 B1 \<union> ball 0 B2 \<subseteq> {a..b}" apply(rule bounded_subset_closed_interval)
himmelma@35172
  1586
    using bounded_Un bounded_ball by auto then guess a b apply-by(erule exE)+
himmelma@35172
  1587
  note ab=conjunctD2[OF this[unfolded Un_subset_iff]]
himmelma@35172
  1588
  guess w using B1(2)[OF ab(1)] .. note w=conjunctD2[OF this]
himmelma@35172
  1589
  guess z using B2(2)[OF ab(2)] .. note z=conjunctD2[OF this]
himmelma@35172
  1590
  have "z = w" using lem[OF w(1) z(1)] by auto
himmelma@35172
  1591
  hence "norm (k1 - k2) \<le> norm (z - k2) + norm (w - k1)"
himmelma@35172
  1592
    using norm_triangle_ineq4[of "k1 - w" "k2 - z"] by(auto simp add: norm_minus_commute) 
himmelma@35172
  1593
  also have "\<dots> < norm (k1 - k2) / 2 + norm (k1 - k2) / 2" apply(rule add_strict_mono) by(rule_tac[!] z(2) w(2))
himmelma@35172
  1594
  finally show False by auto qed
himmelma@35172
  1595
himmelma@35172
  1596
lemma integral_unique[intro]:
himmelma@35172
  1597
  "(f has_integral y) k \<Longrightarrow> integral k f = y"
himmelma@35172
  1598
  unfolding integral_def apply(rule some_equality) by(auto intro: has_integral_unique) 
himmelma@35172
  1599
hoelzl@37489
  1600
lemma has_integral_is_0: fixes f::"'n::ordered_euclidean_space \<Rightarrow> 'a::real_normed_vector" 
himmelma@35172
  1601
  assumes "\<forall>x\<in>s. f x = 0" shows "(f has_integral 0) s"
hoelzl@37489
  1602
proof- have lem:"\<And>a b. \<And>f::'n \<Rightarrow> 'a.
himmelma@35172
  1603
    (\<forall>x\<in>{a..b}. f(x) = 0) \<Longrightarrow> (f has_integral 0) ({a..b})" unfolding has_integral
hoelzl@37489
  1604
  proof(rule,rule) fix a b e and f::"'n \<Rightarrow> 'a"
himmelma@35172
  1605
    assume as:"\<forall>x\<in>{a..b}. f x = 0" "0 < (e::real)"
himmelma@35172
  1606
    show "\<exists>d. gauge d \<and> (\<forall>p. p tagged_division_of {a..b} \<and> d fine p \<longrightarrow> norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) - 0) < e)"
himmelma@35172
  1607
      apply(rule_tac x="\<lambda>x. ball x 1" in exI)  apply(rule,rule gaugeI) unfolding centre_in_ball defer apply(rule open_ball)
himmelma@35172
  1608
    proof(rule,rule,erule conjE) case goal1
himmelma@35172
  1609
      have "(\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) = 0" proof(rule setsum_0',rule)
himmelma@35172
  1610
        fix x assume x:"x\<in>p" have "f (fst x) = 0" using tagged_division_ofD(2-3)[OF goal1(1), of "fst x" "snd x"] using as x by auto
himmelma@35172
  1611
        thus "(\<lambda>(x, k). content k *\<^sub>R f x) x = 0" apply(subst surjective_pairing[of x]) unfolding split_conv by auto
himmelma@35172
  1612
      qed thus ?case using as by auto
himmelma@35172
  1613
    qed auto qed  { presume "\<not> (\<exists>a b. s = {a..b}) \<Longrightarrow> ?thesis"
himmelma@35172
  1614
    thus ?thesis apply-apply(cases "\<exists>a b. s = {a..b}")
himmelma@35172
  1615
      using assms by(auto simp add:has_integral intro:lem) }
himmelma@35172
  1616
  have *:"(\<lambda>x. if x \<in> s then f x else 0) = (\<lambda>x. 0)" apply(rule ext) using assms by auto
himmelma@35172
  1617
  assume "\<not> (\<exists>a b. s = {a..b})" thus ?thesis apply(subst has_integral_alt) unfolding if_not_P *
himmelma@35172
  1618
  apply(rule,rule,rule_tac x=1 in exI,rule) defer apply(rule,rule,rule)
himmelma@35172
  1619
  proof- fix e::real and a b assume "e>0"
hoelzl@37489
  1620
    thus "\<exists>z. ((\<lambda>x::'n. 0::'a) has_integral z) {a..b} \<and> norm (z - 0) < e"
himmelma@35172
  1621
      apply(rule_tac x=0 in exI) apply(rule,rule lem) by auto
himmelma@35172
  1622
  qed auto qed
himmelma@35172
  1623
hoelzl@37489
  1624
lemma has_integral_0[simp]: "((\<lambda>x::'n::ordered_euclidean_space. 0) has_integral 0) s"
himmelma@35172
  1625
  apply(rule has_integral_is_0) by auto 
himmelma@35172
  1626
himmelma@35172
  1627
lemma has_integral_0_eq[simp]: "((\<lambda>x. 0) has_integral i) s \<longleftrightarrow> i = 0"
himmelma@35172
  1628
  using has_integral_unique[OF has_integral_0] by auto
himmelma@35172
  1629
hoelzl@37489
  1630
lemma has_integral_linear: fixes f::"'n::ordered_euclidean_space \<Rightarrow> 'a::real_normed_vector"
himmelma@35172
  1631
  assumes "(f has_integral y) s" "bounded_linear h" shows "((h o f) has_integral ((h y))) s"
himmelma@35172
  1632
proof- interpret bounded_linear h using assms(2) . from pos_bounded guess B .. note B=conjunctD2[OF this,rule_format]
hoelzl@37489
  1633
  have lem:"\<And>f::'n \<Rightarrow> 'a. \<And> y a b.
himmelma@35172
  1634
    (f has_integral y) ({a..b}) \<Longrightarrow> ((h o f) has_integral h(y)) ({a..b})"
himmelma@35172
  1635
  proof(subst has_integral,rule,rule) case goal1
himmelma@35172
  1636
    from pos_bounded guess B .. note B=conjunctD2[OF this,rule_format]
himmelma@35172
  1637
    have *:"e / B > 0" apply(rule divide_pos_pos) using goal1(2) B by auto
himmelma@35172
  1638
    guess g using has_integralD[OF goal1(1) *] . note g=this
himmelma@35172
  1639
    show ?case apply(rule_tac x=g in exI) apply(rule,rule g(1))
himmelma@35172
  1640
    proof(rule,rule,erule conjE) fix p assume as:"p tagged_division_of {a..b}" "g fine p" 
himmelma@35172
  1641
      have *:"\<And>x k. h ((\<lambda>(x, k). content k *\<^sub>R f x) x) = (\<lambda>(x, k). h (content k *\<^sub>R f x)) x" by auto
himmelma@35172
  1642
      have "(\<Sum>(x, k)\<in>p. content k *\<^sub>R (h \<circ> f) x) = setsum (h \<circ> (\<lambda>(x, k). content k *\<^sub>R f x)) p"
himmelma@35172
  1643
        unfolding o_def unfolding scaleR[THEN sym] * by simp
himmelma@35172
  1644
      also have "\<dots> = h (\<Sum>(x, k)\<in>p. content k *\<^sub>R f x)" using setsum[of "\<lambda>(x,k). content k *\<^sub>R f x" p] using as by auto
himmelma@35172
  1645
      finally have *:"(\<Sum>(x, k)\<in>p. content k *\<^sub>R (h \<circ> f) x) = h (\<Sum>(x, k)\<in>p. content k *\<^sub>R f x)" .
himmelma@35172
  1646
      show "norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R (h \<circ> f) x) - h y) < e" unfolding * diff[THEN sym]
himmelma@35172
  1647
        apply(rule le_less_trans[OF B(2)]) using g(2)[OF as] B(1) by(auto simp add:field_simps)
himmelma@35172
  1648
    qed qed { presume "\<not> (\<exists>a b. s = {a..b}) \<Longrightarrow> ?thesis"
himmelma@35172
  1649
    thus ?thesis apply-apply(cases "\<exists>a b. s = {a..b}") using assms by(auto simp add:has_integral intro!:lem) }
himmelma@35172
  1650
  assume as:"\<not> (\<exists>a b. s = {a..b})" thus ?thesis apply(subst has_integral_alt) unfolding if_not_P
himmelma@35172
  1651
  proof(rule,rule) fix e::real  assume e:"0<e"
himmelma@35172
  1652
    have *:"0 < e/B" by(rule divide_pos_pos,rule e,rule B(1))
himmelma@35172
  1653
    guess M using has_integral_altD[OF assms(1) as *,rule_format] . note M=this
himmelma@35172
  1654
    show "\<exists>B>0. \<forall>a b. ball 0 B \<subseteq> {a..b} \<longrightarrow> (\<exists>z. ((\<lambda>x. if x \<in> s then (h \<circ> f) x else 0) has_integral z) {a..b} \<and> norm (z - h y) < e)"
himmelma@35172
  1655
      apply(rule_tac x=M in exI) apply(rule,rule M(1))
himmelma@35172
  1656
    proof(rule,rule,rule) case goal1 guess z using M(2)[OF goal1(1)] .. note z=conjunctD2[OF this]
himmelma@35172
  1657
      have *:"(\<lambda>x. if x \<in> s then (h \<circ> f) x else 0) = h \<circ> (\<lambda>x. if x \<in> s then f x else 0)"
himmelma@35172
  1658
        unfolding o_def apply(rule ext) using zero by auto
himmelma@35172
  1659
      show ?case apply(rule_tac x="h z" in exI,rule) unfolding * apply(rule lem[OF z(1)]) unfolding diff[THEN sym]
himmelma@35172
  1660
        apply(rule le_less_trans[OF B(2)]) using B(1) z(2) by(auto simp add:field_simps)
himmelma@35172
  1661
    qed qed qed
himmelma@35172
  1662
himmelma@35172
  1663
lemma has_integral_cmul:
himmelma@35172
  1664
  shows "(f has_integral k) s \<Longrightarrow> ((\<lambda>x. c *\<^sub>R f x) has_integral (c *\<^sub>R k)) s"
himmelma@35172
  1665
  unfolding o_def[THEN sym] apply(rule has_integral_linear,assumption)
huffman@44282
  1666
  by(rule bounded_linear_scaleR_right)
himmelma@35172
  1667
himmelma@35172
  1668
lemma has_integral_neg:
himmelma@35172
  1669
  shows "(f has_integral k) s \<Longrightarrow> ((\<lambda>x. -(f x)) has_integral (-k)) s"
himmelma@35172
  1670
  apply(drule_tac c="-1" in has_integral_cmul) by auto
himmelma@35172
  1671
hoelzl@37489
  1672
lemma has_integral_add: fixes f::"'n::ordered_euclidean_space \<Rightarrow> 'a::real_normed_vector" 
himmelma@35172
  1673
  assumes "(f has_integral k) s" "(g has_integral l) s"
himmelma@35172
  1674
  shows "((\<lambda>x. f x + g x) has_integral (k + l)) s"
hoelzl@37489
  1675
proof- have lem:"\<And>f g::'n \<Rightarrow> 'a. \<And>a b k l.
himmelma@35172
  1676
    (f has_integral k) ({a..b}) \<Longrightarrow> (g has_integral l) ({a..b}) \<Longrightarrow>
himmelma@35172
  1677
     ((\<lambda>x. f(x) + g(x)) has_integral (k + l)) ({a..b})" proof- case goal1
himmelma@35172
  1678
    show ?case unfolding has_integral proof(rule,rule) fix e::real assume e:"e>0" hence *:"e/2>0" by auto
himmelma@35172
  1679
      guess d1 using has_integralD[OF goal1(1) *] . note d1=this
himmelma@35172
  1680
      guess d2 using has_integralD[OF goal1(2) *] . note d2=this
himmelma@35172
  1681
      show "\<exists>d. gauge d \<and> (\<forall>p. p tagged_division_of {a..b} \<and> d fine p \<longrightarrow> norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R (f x + g x)) - (k + l)) < e)"
himmelma@35172
  1682
        apply(rule_tac x="\<lambda>x. (d1 x) \<inter> (d2 x)" in exI) apply(rule,rule gauge_inter[OF d1(1) d2(1)])
himmelma@35172
  1683
      proof(rule,rule,erule conjE) fix p assume as:"p tagged_division_of {a..b}" "(\<lambda>x. d1 x \<inter> d2 x) fine p"
himmelma@35172
  1684
        have *:"(\<Sum>(x, k)\<in>p. content k *\<^sub>R (f x + g x)) = (\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) + (\<Sum>(x, k)\<in>p. content k *\<^sub>R g x)"
himmelma@35172
  1685
          unfolding scaleR_right_distrib setsum_addf[of "\<lambda>(x,k). content k *\<^sub>R f x" "\<lambda>(x,k). content k *\<^sub>R g x" p,THEN sym]
himmelma@35172
  1686
          by(rule setsum_cong2,auto)
himmelma@35172
  1687
        have "norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R (f x + g x)) - (k + l)) = norm (((\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) - k) + ((\<Sum>(x, k)\<in>p. content k *\<^sub>R g x) - l))"
haftmann@36350
  1688
          unfolding * by(auto simp add:algebra_simps) also let ?res = "\<dots>"
himmelma@35172
  1689
        from as have *:"d1 fine p" "d2 fine p" unfolding fine_inter by auto
himmelma@35172
  1690
        have "?res < e/2 + e/2" apply(rule le_less_trans[OF norm_triangle_ineq])
himmelma@35172
  1691
          apply(rule add_strict_mono) using d1(2)[OF as(1) *(1)] and d2(2)[OF as(1) *(2)] by auto
himmelma@35172
  1692
        finally show "norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R (f x + g x)) - (k + l)) < e" by auto
himmelma@35172
  1693
      qed qed qed { presume "\<not> (\<exists>a b. s = {a..b}) \<Longrightarrow> ?thesis"
himmelma@35172
  1694
    thus ?thesis apply-apply(cases "\<exists>a b. s = {a..b}") using assms by(auto simp add:has_integral intro!:lem) }
himmelma@35172
  1695
  assume as:"\<not> (\<exists>a b. s = {a..b})" thus ?thesis apply(subst has_integral_alt) unfolding if_not_P
himmelma@35172
  1696
  proof(rule,rule) case goal1 hence *:"e/2 > 0" by auto
himmelma@35172
  1697
    from has_integral_altD[OF assms(1) as *] guess B1 . note B1=this[rule_format]
himmelma@35172
  1698
    from has_integral_altD[OF assms(2) as *] guess B2 . note B2=this[rule_format]
himmelma@35172
  1699
    show ?case apply(rule_tac x="max B1 B2" in exI) apply(rule,rule min_max.less_supI1,rule B1)
hoelzl@37489
  1700
    proof(rule,rule,rule) fix a b assume "ball 0 (max B1 B2) \<subseteq> {a..b::'n}"
hoelzl@37489
  1701
      hence *:"ball 0 B1 \<subseteq> {a..b::'n}" "ball 0 B2 \<subseteq> {a..b::'n}" by auto
himmelma@35172
  1702
      guess w using B1(2)[OF *(1)] .. note w=conjunctD2[OF this]
himmelma@35172
  1703
      guess z using B2(2)[OF *(2)] .. note z=conjunctD2[OF this]
himmelma@35172
  1704
      have *:"\<And>x. (if x \<in> s then f x + g x else 0) = (if x \<in> s then f x else 0) + (if x \<in> s then g x else 0)" by auto
himmelma@35172
  1705
      show "\<exists>z. ((\<lambda>x. if x \<in> s then f x + g x else 0) has_integral z) {a..b} \<and> norm (z - (k + l)) < e"
himmelma@35172
  1706
        apply(rule_tac x="w + z" in exI) apply(rule,rule lem[OF w(1) z(1), unfolded *[THEN sym]])
himmelma@35172
  1707
        using norm_triangle_ineq[of "w - k" "z - l"] w(2) z(2) by(auto simp add:field_simps)
himmelma@35172
  1708
    qed qed qed
himmelma@35172
  1709
himmelma@35172
  1710
lemma has_integral_sub:
himmelma@35172
  1711
  shows "(f has_integral k) s \<Longrightarrow> (g has_integral l) s \<Longrightarrow> ((\<lambda>x. f(x) - g(x)) has_integral (k - l)) s"
haftmann@36350
  1712
  using has_integral_add[OF _ has_integral_neg,of f k s g l] unfolding algebra_simps by auto
himmelma@35172
  1713
hoelzl@37489
  1714
lemma integral_0: "integral s (\<lambda>x::'n::ordered_euclidean_space. 0::'m::real_normed_vector) = 0"
himmelma@35172
  1715
  by(rule integral_unique has_integral_0)+
himmelma@35172
  1716
himmelma@35172
  1717
lemma integral_add:
himmelma@35172
  1718
  shows "f integrable_on s \<Longrightarrow> g integrable_on s \<Longrightarrow>
himmelma@35172
  1719
   integral s (\<lambda>x. f x + g x) = integral s f + integral s g"
himmelma@35172
  1720
  apply(rule integral_unique) apply(drule integrable_integral)+
himmelma@35172
  1721
  apply(rule has_integral_add) by assumption+
himmelma@35172
  1722
himmelma@35172
  1723
lemma integral_cmul:
himmelma@35172
  1724
  shows "f integrable_on s \<Longrightarrow> integral s (\<lambda>x. c *\<^sub>R f x) = c *\<^sub>R integral s f"
himmelma@35172
  1725
  apply(rule integral_unique) apply(drule integrable_integral)+
himmelma@35172
  1726
  apply(rule has_integral_cmul) by assumption+
himmelma@35172
  1727
himmelma@35172
  1728
lemma integral_neg:
himmelma@35172
  1729
  shows "f integrable_on s \<Longrightarrow> integral s (\<lambda>x. - f x) = - integral s f"
himmelma@35172
  1730
  apply(rule integral_unique) apply(drule integrable_integral)+
himmelma@35172
  1731
  apply(rule has_integral_neg) by assumption+
himmelma@35172
  1732
himmelma@35172
  1733
lemma integral_sub:
himmelma@35172
  1734
  shows "f integrable_on s \<Longrightarrow> g integrable_on s \<Longrightarrow> integral s (\<lambda>x. f x - g x) = integral s f - integral s g"
himmelma@35172
  1735
  apply(rule integral_unique) apply(drule integrable_integral)+
himmelma@35172
  1736
  apply(rule has_integral_sub) by assumption+
himmelma@35172
  1737
himmelma@35172
  1738
lemma integrable_0: "(\<lambda>x. 0) integrable_on s"
himmelma@35172
  1739
  unfolding integrable_on_def using has_integral_0 by auto
himmelma@35172
  1740
himmelma@35172
  1741
lemma integrable_add:
himmelma@35172
  1742
  shows "f integrable_on s \<Longrightarrow> g integrable_on s \<Longrightarrow> (\<lambda>x. f x + g x) integrable_on s"
himmelma@35172
  1743
  unfolding integrable_on_def by(auto intro: has_integral_add)
himmelma@35172
  1744
himmelma@35172
  1745
lemma integrable_cmul:
himmelma@35172
  1746
  shows "f integrable_on s \<Longrightarrow> (\<lambda>x. c *\<^sub>R f(x)) integrable_on s"
himmelma@35172
  1747
  unfolding integrable_on_def by(auto intro: has_integral_cmul)
himmelma@35172
  1748
himmelma@35172
  1749
lemma integrable_neg:
himmelma@35172
  1750
  shows "f integrable_on s \<Longrightarrow> (\<lambda>x. -f(x)) integrable_on s"
himmelma@35172
  1751
  unfolding integrable_on_def by(auto intro: has_integral_neg)
himmelma@35172
  1752
himmelma@35172
  1753
lemma integrable_sub:
himmelma@35172
  1754
  shows "f integrable_on s \<Longrightarrow> g integrable_on s \<Longrightarrow> (\<lambda>x. f x - g x) integrable_on s"
himmelma@35172
  1755
  unfolding integrable_on_def by(auto intro: has_integral_sub)
himmelma@35172
  1756
himmelma@35172
  1757
lemma integrable_linear:
himmelma@35172
  1758
  shows "f integrable_on s \<Longrightarrow> bounded_linear h \<Longrightarrow> (h o f) integrable_on s"
himmelma@35172
  1759
  unfolding integrable_on_def by(auto intro: has_integral_linear)
himmelma@35172
  1760
himmelma@35172
  1761
lemma integral_linear:
himmelma@35172
  1762
  shows "f integrable_on s \<Longrightarrow> bounded_linear h \<Longrightarrow> integral s (h o f) = h(integral s f)"
himmelma@35172
  1763
  apply(rule has_integral_unique) defer unfolding has_integral_integral 
himmelma@35172
  1764
  apply(drule has_integral_linear,assumption,assumption) unfolding has_integral_integral[THEN sym]
himmelma@35172
  1765
  apply(rule integrable_linear) by assumption+
himmelma@35172
  1766
hoelzl@37489
  1767
lemma integral_component_eq[simp]: fixes f::"'n::ordered_euclidean_space \<Rightarrow> 'm::ordered_euclidean_space"
hoelzl@37489
  1768
  assumes "f integrable_on s" shows "integral s (\<lambda>x. f x $$ k) = integral s f $$ k"
hoelzl@37489
  1769
  unfolding integral_linear[OF assms(1) bounded_linear_component,unfolded o_def] ..
himmelma@36243
  1770
himmelma@35172
  1771
lemma has_integral_setsum:
himmelma@35172
  1772
  assumes "finite t" "\<forall>a\<in>t. ((f a) has_integral (i a)) s"
himmelma@35172
  1773
  shows "((\<lambda>x. setsum (\<lambda>a. f a x) t) has_integral (setsum i t)) s"
himmelma@35172
  1774
proof(insert assms(1) subset_refl[of t],induct rule:finite_subset_induct)
himmelma@35172
  1775
  case (insert x F) show ?case unfolding setsum_insert[OF insert(1,3)]
himmelma@35172
  1776
    apply(rule has_integral_add) using insert assms by auto
himmelma@35172
  1777
qed auto
himmelma@35172
  1778
himmelma@35172
  1779
lemma integral_setsum:
himmelma@35172
  1780
  shows "finite t \<Longrightarrow> \<forall>a\<in>t. (f a) integrable_on s \<Longrightarrow>
himmelma@35172
  1781
  integral s (\<lambda>x. setsum (\<lambda>a. f a x) t) = setsum (\<lambda>a. integral s (f a)) t"
himmelma@35172
  1782
  apply(rule integral_unique) apply(rule has_integral_setsum)
himmelma@35172
  1783
  using integrable_integral by auto
himmelma@35172
  1784
himmelma@35172
  1785
lemma integrable_setsum:
himmelma@35172
  1786
  shows "finite t \<Longrightarrow> \<forall>a \<in> t.(f a) integrable_on s \<Longrightarrow> (\<lambda>x. setsum (\<lambda>a. f a x) t) integrable_on s"
himmelma@35172
  1787
  unfolding integrable_on_def apply(drule bchoice) using has_integral_setsum[of t] by auto
himmelma@35172
  1788
himmelma@35172
  1789
lemma has_integral_eq:
himmelma@35172
  1790
  assumes "\<forall>x\<in>s. f x = g x" "(f has_integral k) s" shows "(g has_integral k) s"
himmelma@35172
  1791
  using has_integral_sub[OF assms(2), of "\<lambda>x. f x - g x" 0]
himmelma@35172
  1792
  using has_integral_is_0[of s "\<lambda>x. f x - g x"] using assms(1) by auto
himmelma@35172
  1793
himmelma@35172
  1794
lemma integrable_eq:
himmelma@35172
  1795
  shows "\<forall>x\<in>s. f x = g x \<Longrightarrow> f integrable_on s \<Longrightarrow> g integrable_on s"
himmelma@35172
  1796
  unfolding integrable_on_def using has_integral_eq[of s f g] by auto
himmelma@35172
  1797
himmelma@35172
  1798
lemma has_integral_eq_eq:
himmelma@35172
  1799
  shows "\<forall>x\<in>s. f x = g x \<Longrightarrow> ((f has_integral k) s \<longleftrightarrow> (g has_integral k) s)"
huffman@36362
  1800
  using has_integral_eq[of s f g] has_integral_eq[of s g f] by rule auto
himmelma@35172
  1801
himmelma@35172
  1802
lemma has_integral_null[dest]:
himmelma@35172
  1803
  assumes "content({a..b}) = 0" shows  "(f has_integral 0) ({a..b})"
himmelma@35172
  1804
  unfolding has_integral apply(rule,rule,rule_tac x="\<lambda>x. ball x 1" in exI,rule) defer
himmelma@35172
  1805
proof(rule,rule,erule conjE) fix e::real assume e:"e>0" thus "gauge (\<lambda>x. ball x 1)" by auto
himmelma@35172
  1806
  fix p assume p:"p tagged_division_of {a..b}" (*"(\<lambda>x. ball x 1) fine p"*)
himmelma@35172
  1807
  have "norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) - 0) = 0" unfolding norm_eq_zero diff_0_right
himmelma@35172
  1808
    using setsum_content_null[OF assms(1) p, of f] . 
himmelma@35172
  1809
  thus "norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) - 0) < e" using e by auto qed
himmelma@35172
  1810
himmelma@35172
  1811
lemma has_integral_null_eq[simp]:
himmelma@35172
  1812
  shows "content({a..b}) = 0 \<Longrightarrow> ((f has_integral i) ({a..b}) \<longleftrightarrow> i = 0)"
himmelma@35172
  1813
  apply rule apply(rule has_integral_unique,assumption) 
himmelma@35172
  1814
  apply(drule has_integral_null,assumption)
himmelma@35172
  1815
  apply(drule has_integral_null) by auto
himmelma@35172
  1816
himmelma@35172
  1817
lemma integral_null[dest]: shows "content({a..b}) = 0 \<Longrightarrow> integral({a..b}) f = 0"
himmelma@35172
  1818
  by(rule integral_unique,drule has_integral_null)
himmelma@35172
  1819
himmelma@35172
  1820
lemma integrable_on_null[dest]: shows "content({a..b}) = 0 \<Longrightarrow> f integrable_on {a..b}"
himmelma@35172
  1821
  unfolding integrable_on_def apply(drule has_integral_null) by auto
himmelma@35172
  1822
himmelma@35172
  1823
lemma has_integral_empty[intro]: shows "(f has_integral 0) {}"
himmelma@35172
  1824
  unfolding empty_as_interval apply(rule has_integral_null) 
himmelma@35172
  1825
  using content_empty unfolding empty_as_interval .
himmelma@35172
  1826
himmelma@35172
  1827
lemma has_integral_empty_eq[simp]: shows "(f has_integral i) {} \<longleftrightarrow> i = 0"
himmelma@35172
  1828
  apply(rule,rule has_integral_unique,assumption) by auto
himmelma@35172
  1829
himmelma@35172
  1830
lemma integrable_on_empty[intro]: shows "f integrable_on {}" unfolding integrable_on_def by auto
himmelma@35172
  1831
himmelma@35172
  1832
lemma integral_empty[simp]: shows "integral {} f = 0"
himmelma@35172
  1833
  apply(rule integral_unique) using has_integral_empty .
himmelma@35172
  1834
hoelzl@37489
  1835
lemma has_integral_refl[intro]: shows "(f has_integral 0) {a..a}" "(f has_integral 0) {a::'a::ordered_euclidean_space}"
nipkow@39302
  1836
proof- have *:"{a} = {a..a}" apply(rule set_eqI) unfolding mem_interval singleton_iff euclidean_eq[where 'a='a]
himmelma@35540
  1837
    apply safe prefer 3 apply(erule_tac x=i in allE) by(auto simp add: field_simps)
himmelma@35540
  1838
  show "(f has_integral 0) {a..a}" "(f has_integral 0) {a}" unfolding *
himmelma@35540
  1839
    apply(rule_tac[!] has_integral_null) unfolding content_eq_0_interior
himmelma@35540
  1840
    unfolding interior_closed_interval using interval_sing by auto qed
himmelma@35172
  1841
himmelma@35172
  1842
lemma integrable_on_refl[intro]: shows "f integrable_on {a..a}" unfolding integrable_on_def by auto
himmelma@35172
  1843
himmelma@35172
  1844
lemma integral_refl: shows "integral {a..a} f = 0" apply(rule integral_unique) by auto
himmelma@35172
  1845
himmelma@35172
  1846
subsection {* Cauchy-type criterion for integrability. *}
himmelma@35172
  1847
hoelzl@37489
  1848
(* XXXXXXX *)
hoelzl@37489
  1849
lemma integrable_cauchy: fixes f::"'n::ordered_euclidean_space \<Rightarrow> 'a::{real_normed_vector,complete_space}" 
himmelma@35172
  1850
  shows "f integrable_on {a..b} \<longleftrightarrow>
himmelma@35172
  1851
  (\<forall>e>0.\<exists>d. gauge d \<and> (\<forall>p1 p2. p1 tagged_division_of {a..b} \<and> d fine p1 \<and>
himmelma@35172
  1852
                            p2 tagged_division_of {a..b} \<and> d fine p2
himmelma@35172
  1853
                            \<longrightarrow> norm(setsum (\<lambda>(x,k). content k *\<^sub>R f x) p1 -
himmelma@35172
  1854
                                     setsum (\<lambda>(x,k). content k *\<^sub>R f x) p2) < e))" (is "?l = (\<forall>e>0. \<exists>d. ?P e d)")
himmelma@35172
  1855
proof assume ?l
himmelma@35172
  1856
  then guess y unfolding integrable_on_def has_integral .. note y=this
himmelma@35172
  1857
  show "\<forall>e>0. \<exists>d. ?P e d" proof(rule,rule) case goal1 hence "e/2 > 0" by auto
himmelma@35172
  1858
    then guess d apply- apply(drule y[rule_format]) by(erule exE,erule conjE) note d=this[rule_format]
himmelma@35172
  1859
    show ?case apply(rule_tac x=d in exI,rule,rule d) apply(rule,rule,rule,(erule conjE)+)
himmelma@35172
  1860
    proof- fix p1 p2 assume as:"p1 tagged_division_of {a..b}" "d fine p1" "p2 tagged_division_of {a..b}" "d fine p2"
himmelma@35172
  1861
      show "norm ((\<Sum>(x, k)\<in>p1. content k *\<^sub>R f x) - (\<Sum>(x, k)\<in>p2. content k *\<^sub>R f x)) < e"
huffman@36587
  1862
        apply(rule dist_triangle_half_l[where y=y,unfolded dist_norm])
himmelma@35172
  1863
        using d(2)[OF conjI[OF as(1-2)]] d(2)[OF conjI[OF as(3-4)]] .
himmelma@35172
  1864
    qed qed
himmelma@35172
  1865
next assume "\<forall>e>0. \<exists>d. ?P e d" hence "\<forall>n::nat. \<exists>d. ?P (inverse(real (n + 1))) d" by auto
himmelma@35172
  1866
  from choice[OF this] guess d .. note d=conjunctD2[OF this[rule_format],rule_format]
himmelma@35172
  1867
  have "\<And>n. gauge (\<lambda>x. \<Inter>{d i x |i. i \<in> {0..n}})" apply(rule gauge_inters) using d(1) by auto
himmelma@35172
  1868
  hence "\<forall>n. \<exists>p. p tagged_division_of {a..b} \<and> (\<lambda>x. \<Inter>{d i x |i. i \<in> {0..n}}) fine p" apply-
himmelma@35172
  1869
  proof case goal1 from this[of n] show ?case apply(drule_tac fine_division_exists) by auto qed
himmelma@35172
  1870
  from choice[OF this] guess p .. note p = conjunctD2[OF this[rule_format]]
himmelma@35172
  1871
  have dp:"\<And>i n. i\<le>n \<Longrightarrow> d i fine p n" using p(2) unfolding fine_inters by auto
himmelma@35172
  1872
  have "Cauchy (\<lambda>n. setsum (\<lambda>(x,k). content k *\<^sub>R (f x)) (p n))"
himmelma@35172
  1873
  proof(rule CauchyI) case goal1 then guess N unfolding real_arch_inv[of e] .. note N=this
himmelma@35172
  1874
    show ?case apply(rule_tac x=N in exI)
himmelma@35172
  1875
    proof(rule,rule,rule,rule) fix m n assume mn:"N \<le> m" "N \<le> n" have *:"N = (N - 1) + 1" using N by auto
himmelma@35172
  1876
      show "norm ((\<Sum>(x, k)\<in>p m. content k *\<^sub>R f x) - (\<Sum>(x, k)\<in>p n. content k *\<^sub>R f x)) < e"
himmelma@35172
  1877
        apply(rule less_trans[OF _ N[THEN conjunct2,THEN conjunct2]]) apply(subst *) apply(rule d(2))
himmelma@35172
  1878
        using dp p(1) using mn by auto 
himmelma@35172
  1879
    qed qed
huffman@44906
  1880
  then guess y unfolding convergent_eq_cauchy[THEN sym] .. note y=this[THEN LIMSEQ_D]
himmelma@35172
  1881
  show ?l unfolding integrable_on_def has_integral apply(rule_tac x=y in exI)
himmelma@35172
  1882
  proof(rule,rule) fix e::real assume "e>0" hence *:"e/2 > 0" by auto
himmelma@35172
  1883
    then guess N1 unfolding real_arch_inv[of "e/2"] .. note N1=this hence N1':"N1 = N1 - 1 + 1" by auto
himmelma@35172
  1884
    guess N2 using y[OF *] .. note N2=this
himmelma@35172
  1885
    show "\<exists>d. gauge d \<and> (\<forall>p. p tagged_division_of {a..b} \<and> d fine p \<longrightarrow> norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) - y) < e)"
himmelma@35172
  1886
      apply(rule_tac x="d (N1 + N2)" in exI) apply rule defer 
himmelma@35172
  1887
    proof(rule,rule,erule conjE) show "gauge (d (N1 + N2))" using d by auto
himmelma@35172
  1888
      fix q assume as:"q tagged_division_of {a..b}" "d (N1 + N2) fine q"
himmelma@35172
  1889
      have *:"inverse (real (N1 + N2 + 1)) < e / 2" apply(rule less_trans) using N1 by auto
himmelma@35172
  1890
      show "norm ((\<Sum>(x, k)\<in>q. content k *\<^sub>R f x) - y) < e" apply(rule norm_triangle_half_r)
himmelma@35172
  1891
        apply(rule less_trans[OF _ *]) apply(subst N1', rule d(2)[of "p (N1+N2)"]) defer
huffman@44906
  1892
        using N2[rule_format,of "N1+N2"]
himmelma@35172
  1893
        using as dp[of "N1 - 1 + 1 + N2" "N1 + N2"] using p(1)[of "N1 + N2"] using N1 by auto qed qed qed
himmelma@35172
  1894
himmelma@35172
  1895
subsection {* Additivity of integral on abutting intervals. *}
himmelma@35172
  1896
hoelzl@37489
  1897
lemma interval_split: fixes a::"'a::ordered_euclidean_space" assumes "k<DIM('a)" shows
hoelzl@37489
  1898
  "{a..b} \<inter> {x. x$$k \<le> c} = {a .. (\<chi>\<chi> i. if i = k then min (b$$k) c else b$$i)}"
hoelzl@37489
  1899
  "{a..b} \<inter> {x. x$$k \<ge> c} = {(\<chi>\<chi> i. if i = k then max (a$$k) c else a$$i) .. b}"
nipkow@39302
  1900
  apply(rule_tac[!] set_eqI) unfolding Int_iff mem_interval mem_Collect_eq using assms by auto
hoelzl@37489
  1901
hoelzl@37489
  1902
lemma content_split: fixes a::"'a::ordered_euclidean_space" assumes "k<DIM('a)" shows
hoelzl@37489
  1903
  "content {a..b} = content({a..b} \<inter> {x. x$$k \<le> c}) + content({a..b} \<inter> {x. x$$k >= c})"
hoelzl@37489
  1904
proof- note simps = interval_split[OF assms] content_closed_interval_cases eucl_le[where 'a='a]
hoelzl@37489
  1905
  { presume "a\<le>b \<Longrightarrow> ?thesis" thus ?thesis apply(cases "a\<le>b") unfolding simps using assms by auto }
hoelzl@37489
  1906
  have *:"{..<DIM('a)} = insert k ({..<DIM('a)} - {k})" "\<And>x. finite ({..<DIM('a)}-{x})" "\<And>x. x\<notin>{..<DIM('a)}-{x}"
hoelzl@37489
  1907
    using assms by auto
hoelzl@37489
  1908
  have *:"\<And>X Y Z. (\<Prod>i\<in>{..<DIM('a)}. Z i (if i = k then X else Y i)) = Z k X * (\<Prod>i\<in>{..<DIM('a)}-{k}. Z i (Y i))"
hoelzl@37489
  1909
    "(\<Prod>i\<in>{..<DIM('a)}. b$$i - a$$i) = (\<Prod>i\<in>{..<DIM('a)}-{k}. b$$i - a$$i) * (b$$k - a$$k)" 
himmelma@35172
  1910
    apply(subst *(1)) defer apply(subst *(1)) unfolding setprod_insert[OF *(2-)] by auto
hoelzl@37489
  1911
  assume as:"a\<le>b" moreover have "\<And>x. min (b $$ k) c = max (a $$ k) c
hoelzl@37489
  1912
    \<Longrightarrow> x* (b$$k - a$$k) = x*(max (a $$ k) c - a $$ k) + x*(b $$ k - max (a $$ k) c)"
himmelma@35172
  1913
    by  (auto simp add:field_simps)
hoelzl@37489
  1914
  moreover have **:"(\<Prod>i<DIM('a). ((\<chi>\<chi> i. if i = k then min (b $$ k) c else b $$ i)::'a) $$ i - a $$ i) = 
hoelzl@37489
  1915
    (\<Prod>i<DIM('a). (if i = k then min (b $$ k) c else b $$ i) - a $$ i)"
hoelzl@37489
  1916
    "(\<Prod>i<DIM('a). b $$ i - ((\<chi>\<chi> i. if i = k then max (a $$ k) c else a $$ i)::'a) $$ i) =
hoelzl@37489
  1917
    (\<Prod>i<DIM('a). b $$ i - (if i = k then max (a $$ k) c else a $$ i))"
hoelzl@37489
  1918
    apply(rule_tac[!] setprod.cong) by auto
hoelzl@37489
  1919
  have "\<not> a $$ k \<le> c \<Longrightarrow> \<not> c \<le> b $$ k \<Longrightarrow> False"
hoelzl@37489
  1920
    unfolding not_le using as[unfolded eucl_le[where 'a='a],rule_format,of k] assms by auto
hoelzl@37489
  1921
  ultimately show ?thesis using assms unfolding simps **
hoelzl@37489
  1922
    unfolding *(1)[of "\<lambda>i x. b$$i - x"] *(1)[of "\<lambda>i x. x - a$$i"] unfolding  *(2) 
hoelzl@37489
  1923
    apply(subst(2) euclidean_lambda_beta''[where 'a='a])
hoelzl@37489
  1924
    apply(subst(3) euclidean_lambda_beta''[where 'a='a]) by auto
himmelma@35172
  1925
qed
himmelma@35172
  1926
hoelzl@37489
  1927
lemma division_split_left_inj: fixes type::"'a::ordered_euclidean_space"
hoelzl@37489
  1928
  assumes "d division_of i" "k1 \<in> d" "k2 \<in> d"  "k1 \<noteq> k2" 
hoelzl@37489
  1929
  "k1 \<inter> {x::'a. x$$k \<le> c} = k2 \<inter> {x. x$$k \<le> c}"and k:"k<DIM('a)"
hoelzl@37489
  1930
  shows "content(k1 \<inter> {x. x$$k \<le> c}) = 0"
himmelma@35172
  1931
proof- note d=division_ofD[OF assms(1)]
hoelzl@37489
  1932
  have *:"\<And>a b::'a. \<And> c. (content({a..b} \<inter> {x. x$$k \<le> c}) = 0 \<longleftrightarrow> interior({a..b} \<inter> {x. x$$k \<le> c}) = {})"
hoelzl@37489
  1933
    unfolding  interval_split[OF k] content_eq_0_interior by auto
himmelma@35172
  1934
  guess u1 v1 using d(4)[OF assms(2)] apply-by(erule exE)+ note uv1=this
himmelma@35172
  1935
  guess u2 v2 using d(4)[OF assms(3)] apply-by(erule exE)+ note uv2=this
himmelma@35172
  1936
  have **:"\<And>s t u. s \<inter> t = {} \<Longrightarrow> u \<subseteq> s \<Longrightarrow> u \<subseteq> t \<Longrightarrow> u = {}" by auto
himmelma@35172
  1937
  show ?thesis unfolding uv1 uv2 * apply(rule **[OF d(5)[OF assms(2-4)]])
himmelma@35172
  1938
    defer apply(subst assms(5)[unfolded uv1 uv2]) unfolding uv1 uv2 by auto qed
hoelzl@37489
  1939
 
hoelzl@37489
  1940
lemma division_split_right_inj: fixes type::"'a::ordered_euclidean_space"
himmelma@35172
  1941
  assumes "d division_of i" "k1 \<in> d" "k2 \<in> d"  "k1 \<noteq> k2"
hoelzl@37489
  1942
  "k1 \<inter> {x::'a. x$$k \<ge> c} = k2 \<inter> {x. x$$k \<ge> c}" and k:"k<DIM('a)"
hoelzl@37489
  1943
  shows "content(k1 \<inter> {x. x$$k \<ge> c}) = 0"
himmelma@35172
  1944
proof- note d=division_ofD[OF assms(1)]
hoelzl@37489
  1945
  have *:"\<And>a b::'a. \<And> c. (content({a..b} \<inter> {x. x$$k >= c}) = 0 \<longleftrightarrow> interior({a..b} \<inter> {x. x$$k >= c}) = {})"
hoelzl@37489
  1946
    unfolding interval_split[OF k] content_eq_0_interior by auto
himmelma@35172
  1947
  guess u1 v1 using d(4)[OF assms(2)] apply-by(erule exE)+ note uv1=this
himmelma@35172
  1948
  guess u2 v2 using d(4)[OF assms(3)] apply-by(erule exE)+ note uv2=this
himmelma@35172
  1949
  have **:"\<And>s t u. s \<inter> t = {} \<Longrightarrow> u \<subseteq> s \<Longrightarrow> u \<subseteq> t \<Longrightarrow> u = {}" by auto
himmelma@35172
  1950
  show ?thesis unfolding uv1 uv2 * apply(rule **[OF d(5)[OF assms(2-4)]])
himmelma@35172
  1951
    defer apply(subst assms(5)[unfolded uv1 uv2]) unfolding uv1 uv2 by auto qed
himmelma@35172
  1952
hoelzl@37489
  1953
lemma tagged_division_split_left_inj: fixes x1::"'a::ordered_euclidean_space"
hoelzl@37489
  1954
  assumes "d tagged_division_of i" "(x1,k1) \<in> d" "(x2,k2) \<in> d" "k1 \<noteq> k2"  "k1 \<inter> {x. x$$k \<le> c} = k2 \<inter> {x. x$$k \<le> c}" 
hoelzl@37489
  1955
  and k:"k<DIM('a)"
hoelzl@37489
  1956
  shows "content(k1 \<inter> {x. x$$k \<le> c}) = 0"
himmelma@35172
  1957
proof- have *:"\<And>a b c. (a,b) \<in> c \<Longrightarrow> b \<in> snd ` c" unfolding image_iff apply(rule_tac x="(a,b)" in bexI) by auto
himmelma@35172
  1958
  show ?thesis apply(rule division_split_left_inj[OF division_of_tagged_division[OF assms(1)]])
himmelma@35172
  1959
    apply(rule_tac[1-2] *) using assms(2-) by auto qed
himmelma@35172
  1960
hoelzl@37489
  1961
lemma tagged_division_split_right_inj: fixes x1::"'a::ordered_euclidean_space"
hoelzl@37489
  1962
  assumes "d tagged_division_of i" "(x1,k1) \<in> d" "(x2,k2) \<in> d" "k1 \<noteq> k2"  "k1 \<inter> {x. x$$k \<ge> c} = k2 \<inter> {x. x$$k \<ge> c}" 
hoelzl@37489
  1963
  and k:"k<DIM('a)"
hoelzl@37489
  1964
  shows "content(k1 \<inter> {x. x$$k \<ge> c}) = 0"
himmelma@35172
  1965
proof- have *:"\<And>a b c. (a,b) \<in> c \<Longrightarrow> b \<in> snd ` c" unfolding image_iff apply(rule_tac x="(a,b)" in bexI) by auto
himmelma@35172
  1966
  show ?thesis apply(rule division_split_right_inj[OF division_of_tagged_division[OF assms(1)]])
himmelma@35172
  1967
    apply(rule_tac[1-2] *) using assms(2-) by auto qed
himmelma@35172
  1968
hoelzl@37489
  1969
lemma division_split: fixes a::"'a::ordered_euclidean_space"
hoelzl@37489
  1970
  assumes "p division_of {a..b}" and k:"k<DIM('a)"
hoelzl@37489
  1971
  shows "{l \<inter> {x. x$$k \<le> c} | l. l \<in> p \<and> ~(l \<inter> {x. x$$k \<le> c} = {})} division_of({a..b} \<inter> {x. x$$k \<le> c})" (is "?p1 division_of ?I1") and 
hoelzl@37489
  1972
        "{l \<inter> {x. x$$k \<ge> c} | l. l \<in> p \<and> ~(l \<inter> {x. x$$k \<ge> c} = {})} division_of ({a..b} \<inter> {x. x$$k \<ge> c})" (is "?p2 division_of ?I2")
hoelzl@37489
  1973
proof(rule_tac[!] division_ofI) note p=division_ofD[OF assms(1)]
himmelma@35172
  1974
  show "finite ?p1" "finite ?p2" using p(1) by auto show "\<Union>?p1 = ?I1" "\<Union>?p2 = ?I2" unfolding p(6)[THEN sym] by auto
himmelma@35172
  1975
  { fix k assume "k\<in>?p1" then guess l unfolding mem_Collect_eq apply-by(erule exE,(erule conjE)+) note l=this
himmelma@35172
  1976
    guess u v using p(4)[OF l(2)] apply-by(erule exE)+ note uv=this
himmelma@35172
  1977
    show "k\<subseteq>?I1" "k \<noteq> {}" "\<exists>a b. k = {a..b}" unfolding l
hoelzl@37489
  1978
      using p(2-3)[OF l(2)] l(3) unfolding uv apply- prefer 3 apply(subst interval_split[OF k]) by auto
himmelma@35172
  1979
    fix k' assume "k'\<in>?p1" then guess l' unfolding mem_Collect_eq apply-by(erule exE,(erule conjE)+) note l'=this
himmelma@35172
  1980
    assume "k\<noteq>k'" thus "interior k \<inter> interior k' = {}" unfolding l l' using p(5)[OF l(2) l'(2)] by auto }
himmelma@35172
  1981
  { fix k assume "k\<in>?p2" then guess l unfolding mem_Collect_eq apply-by(erule exE,(erule conjE)+) note l=this
himmelma@35172
  1982
    guess u v using p(4)[OF l(2)] apply-by(erule exE)+ note uv=this
himmelma@35172
  1983
    show "k\<subseteq>?I2" "k \<noteq> {}" "\<exists>a b. k = {a..b}" unfolding l
hoelzl@37489
  1984
      using p(2-3)[OF l(2)] l(3) unfolding uv apply- prefer 3 apply(subst interval_split[OF k]) by auto
himmelma@35172
  1985
    fix k' assume "k'\<in>?p2" then guess l' unfolding mem_Collect_eq apply-by(erule exE,(erule conjE)+) note l'=this
himmelma@35172
  1986
    assume "k\<noteq>k'" thus "interior k \<inter> interior k' = {}" unfolding l l' using p(5)[OF l(2) l'(2)] by auto }
himmelma@35172
  1987
qed
himmelma@35172
  1988
hoelzl@37489
  1989
lemma has_integral_split: fixes f::"'a::ordered_euclidean_space \<Rightarrow> 'b::real_normed_vector"
hoelzl@37489
  1990
  assumes "(f has_integral i) ({a..b} \<inter> {x. x$$k \<le> c})"  "(f has_integral j) ({a..b} \<inter> {x. x$$k \<ge> c})" and k:"k<DIM('a)"
himmelma@35172
  1991
  shows "(f has_integral (i + j)) ({a..b})"
himmelma@35172
  1992
proof(unfold has_integral,rule,rule) case goal1 hence e:"e/2>0" by auto
hoelzl@37489
  1993
  guess d1 using has_integralD[OF assms(1)[unfolded interval_split[OF k]] e] . note d1=this[unfolded interval_split[THEN sym,OF k]]
hoelzl@37489
  1994
  guess d2 using has_integralD[OF assms(2)[unfolded interval_split[OF k]] e] . note d2=this[unfolded interval_split[THEN sym,OF k]]
hoelzl@37489
  1995
  let ?d = "\<lambda>x. if x$$k = c then (d1 x \<inter> d2 x) else ball x (abs(x$$k - c)) \<inter> d1 x \<inter> d2 x"
himmelma@35172
  1996
  show ?case apply(rule_tac x="?d" in exI,rule) defer apply(rule,rule,(erule conjE)+)
himmelma@35172
  1997
  proof- show "gauge ?d" using d1(1) d2(1) unfolding gauge_def by auto
himmelma@35172
  1998
    fix p assume "p tagged_division_of {a..b}" "?d fine p" note p = this tagged_division_ofD[OF this(1)]
hoelzl@37489
  1999
    have lem0:"\<And>x kk. (x,kk) \<in> p \<Longrightarrow> ~(kk \<inter> {x. x$$k \<le> c} = {}) \<Longrightarrow> x$$k \<le> c"
hoelzl@37489
  2000
         "\<And>x kk. (x,kk) \<in> p \<Longrightarrow> ~(kk \<inter> {x. x$$k \<ge> c} = {}) \<Longrightarrow> x$$k \<ge> c"
himmelma@35172
  2001
    proof- fix x kk assume as:"(x,kk)\<in>p"
hoelzl@37489
  2002
      show "~(kk \<inter> {x. x$$k \<le> c} = {}) \<Longrightarrow> x$$k \<le> c"
himmelma@35172
  2003
      proof(rule ccontr) case goal1
hoelzl@37489
  2004
        from this(2)[unfolded not_le] have "kk \<subseteq> ball x \<bar>x $$ k - c\<bar>"
himmelma@35172
  2005
          using p(2)[unfolded fine_def,rule_format,OF as,unfolded split_conv] by auto
hoelzl@37489
  2006
        hence "\<exists>y. y \<in> ball x \<bar>x $$ k - c\<bar> \<inter> {x. x $$ k \<le> c}" using goal1(1) by blast 
hoelzl@37489
  2007
        then guess y .. hence "\<bar>x $$ k - y $$ k\<bar> < \<bar>x $$ k - c\<bar>" "y$$k \<le> c" apply-apply(rule le_less_trans)
hoelzl@37489
  2008
          using component_le_norm[of "x - y" k] by(auto simp add:dist_norm)
himmelma@35172
  2009
        thus False using goal1(2)[unfolded not_le] by(auto simp add:field_simps)
himmelma@35172
  2010
      qed
hoelzl@37489
  2011
      show "~(kk \<inter> {x. x$$k \<ge> c} = {}) \<Longrightarrow> x$$k \<ge> c"
himmelma@35172
  2012
      proof(rule ccontr) case goal1
hoelzl@37489
  2013
        from this(2)[unfolded not_le] have "kk \<subseteq> ball x \<bar>x $$ k - c\<bar>"
himmelma@35172
  2014
          using p(2)[unfolded fine_def,rule_format,OF as,unfolded split_conv] by auto
hoelzl@37489
  2015
        hence "\<exists>y. y \<in> ball x \<bar>x $$ k - c\<bar> \<inter> {x. x $$ k \<ge> c}" using goal1(1) by blast 
hoelzl@37489
  2016
        then guess y .. hence "\<bar>x $$ k - y $$ k\<bar> < \<bar>x $$ k - c\<bar>" "y$$k \<ge> c" apply-apply(rule le_less_trans)
hoelzl@37489
  2017
          using component_le_norm[of "x - y" k] by(auto simp add:dist_norm)
himmelma@35172
  2018
        thus False using goal1(2)[unfolded not_le] by(auto simp add:field_simps)
himmelma@35172
  2019
      qed
himmelma@35172
  2020
    qed
himmelma@35172
  2021
himmelma@35172
  2022
    have lem1: "\<And>f P Q. (\<forall>x k. (x,k) \<in> {(x,f k) | x k. P x k} \<longrightarrow> Q x k) \<longleftrightarrow> (\<forall>x k. P x k \<longrightarrow> Q x (f k))" by auto
himmelma@35172
  2023
    have lem2: "\<And>f s P f. finite s \<Longrightarrow> finite {(x,f k) | x k. (x,k) \<in> s \<and> P x k}"
himmelma@35172
  2024
    proof- case goal1 thus ?case apply-apply(rule finite_subset[of _ "(\<lambda>(x,k). (x,f k)) ` s"]) by auto qed
huffman@44170
  2025
    have lem3: "\<And>g::'a set \<Rightarrow> 'a set. finite p \<Longrightarrow>
himmelma@35172
  2026
      setsum (\<lambda>(x,k). content k *\<^sub>R f x) {(x,g k) |x k. (x,k) \<in> p \<and> ~(g k = {})}
himmelma@35172
  2027
               = setsum (\<lambda>(x,k). content k *\<^sub>R f x) ((\<lambda>(x,k). (x,g k)) ` p)"
himmelma@35172
  2028
      apply(rule setsum_mono_zero_left) prefer 3
huffman@44170
  2029
    proof fix g::"'a set \<Rightarrow> 'a set" and i::"('a) \<times> (('a) set)"
himmelma@35172
  2030
      assume "i \<in> (\<lambda>(x, k). (x, g k)) ` p - {(x, g k) |x k. (x, k) \<in> p \<and> g k \<noteq> {}}"
himmelma@35172
  2031
      then obtain x k where xk:"i=(x,g k)" "(x,k)\<in>p" "(x,g k) \<notin> {(x, g k) |x k. (x, k) \<in> p \<and> g k \<noteq> {}}" by auto
himmelma@35172
  2032
      have "content (g k) = 0" using xk using content_empty by auto
himmelma@35172
  2033
      thus "(\<lambda>(x, k). content k *\<^sub>R f x) i = 0" unfolding xk split_conv by auto
himmelma@35172
  2034
    qed auto
himmelma@35172
  2035
    have lem4:"\<And>g. (\<lambda>(x,l). content (g l) *\<^sub>R f x) = (\<lambda>(x,l). content l *\<^sub>R f x) o (\<lambda>(x,l). (x,g l))" apply(rule ext) by auto
himmelma@35172
  2036
hoelzl@37489
  2037
    let ?M1 = "{(x,kk \<inter> {x. x$$k \<le> c}) |x kk. (x,kk) \<in> p \<and> kk \<inter> {x. x$$k \<le> c} \<noteq> {}}"
himmelma@35172
  2038
    have "norm ((\<Sum>(x, k)\<in>?M1. content k *\<^sub>R f x) - i) < e/2" apply(rule d1(2),rule tagged_division_ofI)
himmelma@35172
  2039
      apply(rule lem2 p(3))+ prefer 6 apply(rule fineI)
hoelzl@37489
  2040
    proof- show "\<Union>{k. \<exists>x. (x, k) \<in> ?M1} = {a..b} \<inter> {x. x$$k \<le> c}" unfolding p(8)[THEN sym] by auto
himmelma@35172
  2041
      fix x l assume xl:"(x,l)\<in>?M1"
himmelma@35172
  2042
      then guess x' l' unfolding mem_Collect_eq apply- unfolding Pair_eq apply((erule exE)+,(erule conjE)+) .  note xl'=this
himmelma@35172
  2043
      have "l' \<subseteq> d1 x'" apply(rule order_trans[OF fineD[OF p(2) xl'(3)]]) by auto
himmelma@35172
  2044
      thus "l \<subseteq> d1 x" unfolding xl' by auto
hoelzl@37489
  2045
      show "x\<in>l" "l \<subseteq> {a..b} \<inter> {x. x $$ k \<le> c}" unfolding xl' using p(4-6)[OF xl'(3)] using xl'(4)
himmelma@35172
  2046
        using lem0(1)[OF xl'(3-4)] by auto
nipkow@44890
  2047
      show  "\<exists>a b. l = {a..b}" unfolding xl' using p(6)[OF xl'(3)] by(fastforce simp add: interval_split[OF k,where c=c])
himmelma@35172
  2048
      fix y r let ?goal = "interior l \<inter> interior r = {}" assume yr:"(y,r)\<in>?M1"
himmelma@35172
  2049
      then guess y' r' unfolding mem_Collect_eq apply- unfolding Pair_eq apply((erule exE)+,(erule conjE)+) .  note yr'=this
himmelma@35172
  2050
      assume as:"(x,l) \<noteq> (y,r)" show "interior l \<inter> interior r = {}"
himmelma@35172
  2051
      proof(cases "l' = r' \<longrightarrow> x' = y'")
himmelma@35172
  2052
        case False thus ?thesis using p(7)[OF xl'(3) yr'(3)] using as unfolding xl' yr' by auto
himmelma@35172
  2053
      next case True hence "l' \<noteq> r'" using as unfolding xl' yr' by auto
himmelma@35172
  2054
        thus ?thesis using p(7)[OF xl'(3) yr'(3)] using as unfolding xl' yr' by auto
himmelma@35172
  2055
      qed qed moreover
himmelma@35172
  2056
hoelzl@37489
  2057
    let ?M2 = "{(x,kk \<inter> {x. x$$k \<ge> c}) |x kk. (x,kk) \<in> p \<and> kk \<inter> {x. x$$k \<ge> c} \<noteq> {}}" 
himmelma@35172
  2058
    have "norm ((\<Sum>(x, k)\<in>?M2. content k *\<^sub>R f x) - j) < e/2" apply(rule d2(2),rule tagged_division_ofI)
himmelma@35172
  2059
      apply(rule lem2 p(3))+ prefer 6 apply(rule fineI)
hoelzl@37489
  2060
    proof- show "\<Union>{k. \<exists>x. (x, k) \<in> ?M2} = {a..b} \<inter> {x. x$$k \<ge> c}" unfolding p(8)[THEN sym] by auto
himmelma@35172
  2061
      fix x l assume xl:"(x,l)\<in>?M2"
himmelma@35172
  2062
      then guess x' l' unfolding mem_Collect_eq apply- unfolding Pair_eq apply((erule exE)+,(erule conjE)+) .  note xl'=this
himmelma@35172
  2063
      have "l' \<subseteq> d2 x'" apply(rule order_trans[OF fineD[OF p(2) xl'(3)]]) by auto
himmelma@35172
  2064
      thus "l \<subseteq> d2 x" unfolding xl' by auto
hoelzl@37489
  2065
      show "x\<in>l" "l \<subseteq> {a..b} \<inter> {x. x $$ k \<ge> c}" unfolding xl' using p(4-6)[OF xl'(3)] using xl'(4)
himmelma@35172
  2066
        using lem0(2)[OF xl'(3-4)] by auto
nipkow@44890
  2067
      show  "\<exists>a b. l = {a..b}" unfolding xl' using p(6)[OF xl'(3)] by(fastforce simp add: interval_split[OF k, where c=c])
himmelma@35172
  2068
      fix y r let ?goal = "interior l \<inter> interior r = {}" assume yr:"(y,r)\<in>?M2"
himmelma@35172
  2069
      then guess y' r' unfolding mem_Collect_eq apply- unfolding Pair_eq apply((erule exE)+,(erule conjE)+) .  note yr'=this
himmelma@35172
  2070
      assume as:"(x,l) \<noteq> (y,r)" show "interior l \<inter> interior r = {}"
himmelma@35172
  2071
      proof(cases "l' = r' \<longrightarrow> x' = y'")
himmelma@35172
  2072
        case False thus ?thesis using p(7)[OF xl'(3) yr'(3)] using as unfolding xl' yr' by auto
himmelma@35172
  2073
      next case True hence "l' \<noteq> r'" using as unfolding xl' yr' by auto
himmelma@35172
  2074
        thus ?thesis using p(7)[OF xl'(3) yr'(3)] using as unfolding xl' yr' by auto
himmelma@35172
  2075
      qed qed ultimately
himmelma@35172
  2076
himmelma@35172
  2077
    have "norm (((\<Sum>(x, k)\<in>?M1. content k *\<^sub>R f x) - i) + ((\<Sum>(x, k)\<in>?M2. content k *\<^sub>R f x) - j)) < e/2 + e/2"
himmelma@35172
  2078
      apply- apply(rule norm_triangle_lt) by auto
hoelzl@37489
  2079
    also { have *:"\<And>x y. x = (0::real) \<Longrightarrow> x *\<^sub>R (y::'b) = 0" using scaleR_zero_left by auto
himmelma@35172
  2080
      have "((\<Sum>(x, k)\<in>?M1. content k *\<^sub>R f x) - i) + ((\<Sum>(x, k)\<in>?M2. content k *\<^sub>R f x) - j)
himmelma@35172
  2081
       = (\<Sum>(x, k)\<in>?M1. content k *\<^sub>R f x) + (\<Sum>(x, k)\<in>?M2. content k *\<^sub>R f x) - (i + j)" by auto
hoelzl@37489
  2082
      also have "\<dots> = (\<Sum>(x, ka)\<in>p. content (ka \<inter> {x. x $$ k \<le> c}) *\<^sub>R f x) +
hoelzl@37489
  2083
        (\<Sum>(x, ka)\<in>p. content (ka \<inter> {x. c \<le> x $$ k}) *\<^sub>R f x) - (i + j)"
himmelma@35172
  2084
        unfolding lem3[OF p(3)] apply(subst setsum_reindex_nonzero[OF p(3)]) defer apply(subst setsum_reindex_nonzero[OF p(3)])
himmelma@35172
  2085
        defer unfolding lem4[THEN sym] apply(rule refl) unfolding split_paired_all split_conv apply(rule_tac[!] *)
hoelzl@37489
  2086
      proof- case goal1 thus ?case apply- apply(rule tagged_division_split_left_inj [OF p(1), of a b aa ba]) using k by auto
hoelzl@37489
  2087
      next case   goal2 thus ?case apply- apply(rule tagged_division_split_right_inj[OF p(1), of a b aa ba]) using k by auto
himmelma@35172
  2088
      qed also note setsum_addf[THEN sym]
hoelzl@37489
  2089
      also have *:"\<And>x. x\<in>p \<Longrightarrow> (\<lambda>(x, ka). content (ka \<inter> {x. x $$ k \<le> c}) *\<^sub>R f x) x + (\<lambda>(x, ka). content (ka \<inter> {x. c \<le> x $$ k}) *\<^sub>R f x) x
himmelma@35172
  2090
        = (\<lambda>(x,ka). content ka *\<^sub>R f x) x" unfolding split_paired_all split_conv
himmelma@35172
  2091
      proof- fix a b assume "(a,b) \<in> p" from p(6)[OF this] guess u v apply-by(erule exE)+ note uv=this
hoelzl@37489
  2092
        thus "content (b \<inter> {x. x $$ k \<le> c}) *\<^sub>R f a + content (b \<inter> {x. c \<le> x $$ k}) *\<^sub>R f a = content b *\<^sub>R f a"
hoelzl@37489
  2093
          unfolding scaleR_left_distrib[THEN sym] unfolding uv content_split[OF k,of u v c] by auto
himmelma@35172
  2094
      qed note setsum_cong2[OF this]
hoelzl@37489
  2095
      finally have "(\<Sum>(x, k)\<in>{(x, kk \<inter> {x. x $$ k \<le> c}) |x kk. (x, kk) \<in> p \<and> kk \<inter> {x. x $$ k \<le> c} \<noteq> {}}. content k *\<^sub>R f x) - i +
hoelzl@37489
  2096
        ((\<Sum>(x, k)\<in>{(x, kk \<inter> {x. c \<le> x $$ k}) |x kk. (x, kk) \<in> p \<and> kk \<inter> {x. c \<le> x $$ k} \<noteq> {}}. content k *\<^sub>R f x) - j) =
himmelma@35172
  2097
        (\<Sum>(x, ka)\<in>p. content ka *\<^sub>R f x) - (i + j)" by auto }
himmelma@35172
  2098
    finally show "norm ((\<Sum>(x, k)\<in>p. content k *\<^sub>R f x) - (i + j)) < e" by auto qed qed
himmelma@35172
  2099
hoelzl@37489
  2100
(*lemma has_integral_split_cart: fixes f::"real^'n \<Rightarrow> 'a::real_normed_vector"
hoelzl@37489
  2101
  assumes "(f has_integral i) ({a..b} \<inter> {x. x$k \<le> c})"  "(f has_integral j) ({a..b} \<inter> {x. x$k \<ge> c})"
hoelzl@37489
  2102
  shows "(f has_integral (i + j)) ({a..b})" *)
hoelzl@37489
  2103
himmelma@35172
  2104
subsection {* A sort of converse, integrability on subintervals. *}
himmelma@35172
  2105
hoelzl@37489
  2106
lemma tagged_division_union_interval: fixes a::"'a::ordered_euclidean_space"
hoelzl@37489
  2107
  assumes "p1 tagged_division_of ({a..b} \<inter> {x. x$$k \<le> (c::real)})"  "p2 tagged_division_of ({a..b} \<inter> {x. x$$k \<ge> c})"
hoelzl@37489
  2108
  and k:"k<DIM('a)"
himmelma@35172
  2109
  shows "(p1 \<union> p2) tagged_division_of ({a..b})"
hoelzl@37489
  2110
proof- have *:"{a..b} = ({a..b} \<inter> {x. x$$k \<le> c}) \<union> ({a..b} \<inter> {x. x$$k \<ge> c})" by auto
hoelzl@37489
  2111
  show ?thesis apply(subst *) apply(rule tagged_division_union[OF assms(1-2)])
hoelzl@37489
  2112
    unfolding interval_split[OF k] interior_closed_interval using k
hoelzl@37489
  2113
    by(auto simp add: eucl_less[where 'a='a] elim!:allE[where x=k]) qed
hoelzl@37489
  2114
hoelzl@37489
  2115
lemma has_integral_separate_sides: fixes f::"'a::ordered_euclidean_space \<Rightarrow> 'b::real_normed_vector"
hoelzl@37489
  2116
  assumes "(f has_integral i) ({a..b})" "e>0" and k:"k<DIM('a)"
hoelzl@37489
  2117
  obtains d where "gauge d" "(\<forall>p1 p2. p1 tagged_division_of ({a..b} \<inter> {x. x$$k \<le> c}) \<and> d fine p1 \<and>
hoelzl@37489
  2118
                                p2 tagged_division_of ({a..b} \<inter> {x. x$$k \<ge> c}) \<and> d fine p2
himmelma@35172
  2119
                                \<longrightarrow> norm((setsum (\<lambda>(x,k). content k *\<^sub>R f x) p1 +
himmelma@35172
  2120
                                          setsum (\<lambda>(x,k). content k *\<^sub>R f x) p2) - i) < e)"
hoelzl@37489
  2121
proof- guess d using has_integralD[OF assms(1-2)] . note d=this
himmelma@35172
  2122
  show ?thesis apply(rule that[of d]) apply(rule d) apply(rule,rule,rule,(erule conjE)+)
hoelzl@37489
  2123
  proof- fix p1 p2 assume "p1 tagged_division_of {a..b} \<inter> {x. x $$ k \<le> c}" "d fine p1" note p1=tagged_division_ofD[OF this(1)] this
hoelzl@37489
  2124
                   assume "p2 tagged_division_of {a..b} \<inter> {x. c \<le> x $$ k}" "d fine p2" note p2=tagged_division_ofD[OF this(1)] this
himmelma@35172
  2125
    note tagged_division_union_interval[OF p1(7) p2(7)] note p12 = tagged_division_ofD[OF this] this
himmelma@35172
  2126
    have "norm ((\<Sum>(x, k)\<in>p1. content k *\<^sub>R f x) + (\<Sum>(x, k)\<in>p2. content k *\<^sub>R f x) - i) = norm ((\<Sum>(x, k)\<in>p1 \<union> p2. content k *\<^sub>R f x) - i)"
himmelma@35172
  2127
      apply(subst setsum_Un_zero) apply(rule p1 p2)+ apply(rule) unfolding split_paired_all split_conv
himmelma@35172
  2128
    proof- fix a b assume ab:"(a,b) \<in> p1 \<inter> p2"
himmelma@35172
  2129
      have "(a,b) \<in> p1" using ab by auto from p1(4)[OF this] guess u v apply-by(erule exE)+ note uv =this
nipkow@44890
  2130
      have "b \<subseteq> {x. x$$k = c}" using ab p1(3)[of a b] p2(3)[of a b] by fastforce
hoelzl@37489
  2131
      moreover have "interior {x::'a. x $$ k = c} = {}" 
hoelzl@37489
  2132
      proof(rule ccontr) case goal1 then obtain x where x:"x\<in>interior {x::'a. x$$k = c}" by auto
himmelma@35172
  2133
        then guess e unfolding mem_interior .. note e=this
nipkow@44890
  2134
        have x:"x$$k = c" using x interior_subset by fastforce
hoelzl@37489
  2135
        have *:"\<And>i. i<DIM('a) \<Longrightarrow> \<bar>(x - (x + (\<chi>\<chi> i. if i = k then e / 2 else 0))) $$ i\<bar>
hoelzl@37489
  2136
          = (if i = k then e/2 else 0)" using e by auto
hoelzl@37489
  2137
        have "(\<Sum>i<DIM('a). \<bar>(x - (x + (\<chi>\<chi> i. if i = k then e / 2 else 0))) $$ i\<bar>) =
hoelzl@37489
  2138
          (\<Sum>i<DIM('a). (if i = k then e / 2 else 0))" apply(rule setsum_cong2) apply(subst *) by auto
hoelzl@37489
  2139
        also have "... < e" apply(subst setsum_delta) using e by auto 
hoelzl@37489
  2140
        finally have "x + (\<chi>\<chi> i. if i = k then e/2 else 0) \<in> ball x e" unfolding mem_ball dist_norm
hoelzl@37489
  2141
          by(rule le_less_trans[OF norm_le_l1])
hoelzl@37489
  2142
        hence "x + (\<chi>\<chi> i. if i = k then e/2 else 0) \<in> {x. x$$k = c}" using e by auto
hoelzl@37489
  2143
        thus False unfolding mem_Collect_eq using e x k by auto
huffman@44522
  2144
      qed ultimately have "content b = 0" unfolding uv content_eq_0_interior apply-apply(drule interior_mono) by auto
himmelma@35172
  2145
      thus "content b *\<^sub>R f a = 0" by auto
himmelma@35172
  2146
    qed auto
hoelzl@37489
  2147
    also have "\<dots> < e" by(rule k d(2) p12 fine_union p1 p2)+
himmelma@35172
  2148
    finally show "norm ((\<Sum>(x, k)\<in>p1. content k *\<^sub>R f x) + (\<Sum>(x, k)\<in>p2. content k *\<^sub>R f x) - i) < e" . qed qed
himmelma@35172
  2149
hoelzl@37489
  2150
lemma integrable_split[intro]: fixes f::"'a::ordered_euclidean_space \<Rightarrow> 'b::{real_normed_vector,complete_space}"
hoelzl@37489
  2151
  assumes "f integrable_on {a..b}" and k:"k<DIM('a)"
hoelzl@37489
  2152
  shows "f integrable_on ({a..b} \<inter> {x. x$$k \<le> c})" (is ?t1) and "f integrable_on ({a..b} \<inter> {x. x$$k \<ge> c})" (is ?t2) 
hoelzl@37489
  2153
proof- guess y using assms(1) unfolding integrable_on_def .. note y=this
hoelzl@37489
  2154
  def b' \<equiv> "(\<chi>\<chi> i. if i = k then min (b$$k) c else b$$i)::'a"
hoelzl@37489
  2155
  and a' \<equiv> "(\<chi>\<chi> i. if i = k then max (a$$k) c else a$$i)::'a"
hoelzl@37489
  2156
  show ?t1 ?t2 unfolding interval_split[OF k] integrable_cauchy unfolding interval_split[THEN sym,OF k]
himmelma@35172
  2157
  proof(rule_tac[!] allI impI)+ fix e::real assume "e>0" hence "e/2>0" by auto
hoelzl@37489
  2158
    from has_integral_separate_sides[OF y this k,of c] guess d . note d=this[rule_format]
hoelzl@37489
  2159
    let ?P = "\<lambda>A. \<exists>d. gauge d \<and> (\<forall>p1 p2. p1 tagged_division_of {a..b} \<inter> A \<and> d fine p1
hoelzl@37489
  2160
      \<and> p2 tagged_division_of {a..b} \<inter> A \<and> d fine p2 \<longrightarrow>
hoelzl@37489
  2161
      norm ((\<Sum>(x, k)\<in>p1. content k *\<^sub>R f x) - (\<Sum>(x, k)\<in>p2. content k *\<^sub>R f x)) < e)"
hoelzl@37489
  2162
    show "?P {x. x $$ k \<le> c}" apply(rule_tac x=d in exI) apply(rule,rule d) apply(rule,rule,rule)
hoelzl@37489
  2163
    proof- fix p1 p2 assume as:"p1 tagged_division_of {a..b} \<inter> {x. x $$ k \<le> c} \<and> d fine p1
hoelzl@37489
  2164
        \<and> p2 tagged_division_of {a..b} \<inter> {x. x $$ k \<le> c} \<and> d fine p2"
himmelma@35172
  2165
      show "norm ((\<Sum>(x, k)\<in>p1. content k *\<^sub>R f x) - (\<Sum>(x, k)\<in>p2. content k *\<^sub>R f x)) < e"
himmelma@35172
  2166
      proof- guess p using fine_division_exists[OF d(1), of a' b] . note p=this
himmelma@35172
  2167
        show ?thesis using norm_triangle_half_l[OF d(2)[of p1 p] d(2)[of p2 p]]
hoelzl@37489
  2168
          using as unfolding interval_split[OF k] b'_def[symmetric] a'_def[symmetric]
haftmann@36350
  2169
          using p using assms by(auto simp add:algebra_simps)
himmelma@35172
  2170
      qed qed  
hoelzl@37489
  2171
    show "?P {x. x $$ k \<ge> c}" apply(rule_tac x=d in exI) apply(rule,rule d) apply(rule,rule,rule)
hoelzl@37489
  2172
    proof- fix p1 p2 assume as:"p1 tagged_division_of {a..b} \<inter> {x. x $$ k \<ge> c} \<and> d fine p1
hoelzl@37489
  2173
        \<and> p2 tagged_division_of {a..b} \<inter> {x. x $$ k \<ge> c} \<and> d fine p2"
himmelma@35172
  2174
      show "norm ((\<Sum>(x, k)\<in>p1. content k *\<^sub>R f x) - (\<Sum>(x, k)\<in>p2. content k *\<^sub>R f x)) < e"
himmelma@35172
  2175
      proof- guess p using fine_division_exists[OF d(1), of a b'] . note p=this
himmelma@35172
  2176
        show ?thesis using norm_triangle_half_l[OF d(2)[of p p1] d(2)[of p p2]]
hoelzl@37489
  2177
          using as unfolding interval_split[OF k] b'_def[symmetric] a'_def[symmetric]
haftmann@36350
  2178
          using p using assms by(auto simp add:algebra_simps) qed qed qed qed
himmelma@35172
  2179
himmelma@35172
  2180
subsection {* Generalized notion of additivity. *}
himmelma@35172
  2181
himmelma@35172
  2182
definition "neutral opp = (SOME x. \<forall>y. opp x y = y \<and> opp y x = y)"
himmelma@35172
  2183
hoelzl@37489
  2184
definition operative :: "('a \<Rightarrow> 'a \<Rightarrow> 'a) \<Rightarrow> (('b::ordered_euclidean_space) set \<Rightarrow> 'a) \<Rightarrow> bool" where
himmelma@35172
  2185
  "operative opp f \<equiv> 
himmelma@35172
  2186
    (\<forall>a b. content {a..b} = 0 \<longrightarrow> f {a..b} = neutral(opp)) \<and>
hoelzl@37489
  2187
    (\<forall>a b c. \<forall>k<DIM('b). f({a..b}) =
hoelzl@37489
  2188
                   opp (f({a..b} \<inter> {x. x$$k \<le> c}))
hoelzl@37489
  2189
                       (f({a..b} \<inter> {x. x$$k \<ge> c})))"
hoelzl@37489
  2190
hoelzl@37489
  2191
lemma operativeD[dest]: fixes type::"'a::ordered_euclidean_space"  assumes "operative opp f"
hoelzl@37489
  2192
  shows "\<And>a b. content {a..b} = 0 \<Longrightarrow> f {a..b::'a} = neutral(opp)"
hoelzl@37489
  2193
  "\<And>a b c k. k<DIM('a) \<Longrightarrow> f({a..b}) = opp (f({a..b} \<inter> {x. x$$k \<le> c})) (f({a..b} \<inter> {x. x$$k \<ge> c}))"
himmelma@35172
  2194
  using assms unfolding operative_def by auto
himmelma@35172
  2195
himmelma@35172
  2196
lemma operative_trivial:
himmelma@35172
  2197
 "operative opp f \<Longrightarrow> content({a..b}) = 0 \<Longrightarrow> f({a..b}) = neutral opp"
himmelma@35172
  2198
  unfolding operative_def by auto
himmelma@35172
  2199
himmelma@35172
  2200
lemma property_empty_interval:
himmelma@35172
  2201
 "(\<forall>a b. content({a..b}) = 0 \<longrightarrow> P({a..b})) \<Longrightarrow> P {}" 
himmelma@35172
  2202
  using content_empty unfolding empty_as_interval by auto
himmelma@35172
  2203
himmelma@35172
  2204
lemma operative_empty: "operative opp f \<Longrightarrow> f {} = neutral opp"
himmelma@35172
  2205
  unfolding operative_def apply(rule property_empty_interval) by auto
himmelma@35172
  2206
himmelma@35172
  2207
subsection {* Using additivity of lifted function to encode definedness. *}
himmelma@35172
  2208
himmelma@35172
  2209
lemma forall_option: "(\<forall>x. P x) \<longleftrightarrow> P None \<and> (\<forall>x. P(Some x))"
huffman@36362
  2210
  by (metis option.nchotomy)
himmelma@35172
  2211
wenzelm@49197
  2212
lemma exists_option: "(\<exists>x. P x) \<longleftrightarrow> P None \<or> (\<exists>x. P(Some x))"
huffman@36362
  2213
  by (metis option.nchotomy)
himmelma@35172
  2214
wenzelm@49197
  2215
fun lifted
wenzelm@49197
  2216
where
wenzelm@49197
  2217
  "lifted (opp::'a\<Rightarrow>'a\<Rightarrow>'b) (Some x) (Some y) = Some (opp x y)"
wenzelm@49197
  2218
| "lifted opp None _ = (None::'b option)"
wenzelm@49197
  2219
| "lifted opp _ None = None"
himmelma@35172
  2220
himmelma@35172
  2221
lemma lifted_simp_1[simp]: "lifted opp v None = None"
wenzelm@49197
  2222
  by (induct v) auto
himmelma@35172
  2223
himmelma@35172
  2224
definition "monoidal opp \<equiv>  (\<forall>x y. opp x y = opp y x) \<and>
himmelma@35172
  2225
                   (\<forall>x y z. opp x (opp y z) = opp (opp x y) z) \<and>
himmelma@35172
  2226
                   (\<forall>x. opp (neutral opp) x = x)"
himmelma@35172
  2227
wenzelm@49197
  2228
lemma monoidalI:
wenzelm@49197
  2229
  assumes "\<And>x y. opp x y = opp y x"
himmelma@35172
  2230
  "\<And>x y z. opp x (opp y z) = opp (opp x y) z"
himmelma@35172
  2231
  "\<And>x. opp (neutral opp) x = x" shows "monoidal opp"
nipkow@44890
  2232
  unfolding monoidal_def using assms by fastforce
himmelma@35172
  2233
wenzelm@49197
  2234
lemma monoidal_ac:
wenzelm@49197
  2235
  assumes "monoidal opp"
himmelma@35172
  2236
  shows "opp (neutral opp) a = a" "opp a (neutral opp) = a" "opp a b = opp b a"
himmelma@35172
  2237
  "opp (opp a b) c = opp a (opp b c)"  "opp a (opp b c) = opp b (opp a c)"
wenzelm@49197
  2238
  using assms unfolding monoidal_def by metis+
himmelma@35172
  2239
himmelma@35172
  2240
lemma monoidal_simps[simp]: assumes "monoidal opp"
himmelma@35172
  2241
  shows "opp (neutral opp) a = a" "opp a (neutral opp) = a"
himmelma@35172
  2242
  using monoidal_ac[OF assms] by auto
himmelma@35172
  2243
himmelma@35172
  2244
lemma neutral_lifted[cong]: assumes "monoidal opp"
himmelma@35172
  2245
  shows "neutral (lifted opp) = Some(neutral opp)"
himmelma@35172
  2246
  apply(subst neutral_def) apply(rule some_equality) apply(rule,induct_tac y) prefer 3
wenzelm@49197
  2247
proof -
wenzelm@49197
  2248
  fix x assume "\<forall>y. lifted opp x y = y \<and> lifted opp y x = y"
wenzelm@49197
  2249
  thus "x = Some (neutral opp)"