src/HOL/Real.thy
author haftmann
Tue Nov 19 10:05:53 2013 +0100 (2013-11-19)
changeset 54489 03ff4d1e6784
parent 54281 b01057e72233
child 54863 82acc20ded73
permissions -rw-r--r--
eliminiated neg_numeral in favour of - (numeral _)
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(*  Title:      HOL/Real.thy
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    Author:     Jacques D. Fleuriot, University of Edinburgh, 1998
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    Author:     Larry Paulson, University of Cambridge
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    Author:     Jeremy Avigad, Carnegie Mellon University
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    Author:     Florian Zuleger, Johannes Hoelzl, and Simon Funke, TU Muenchen
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    Conversion to Isar and new proofs by Lawrence C Paulson, 2003/4
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    Construction of Cauchy Reals by Brian Huffman, 2010
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*)
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header {* Development of the Reals using Cauchy Sequences *}
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theory Real
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imports Rat Conditionally_Complete_Lattices
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begin
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text {*
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  This theory contains a formalization of the real numbers as
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  equivalence classes of Cauchy sequences of rationals.  See
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  @{file "~~/src/HOL/ex/Dedekind_Real.thy"} for an alternative
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  construction using Dedekind cuts.
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*}
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subsection {* Preliminary lemmas *}
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lemma add_diff_add:
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  fixes a b c d :: "'a::ab_group_add"
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  shows "(a + c) - (b + d) = (a - b) + (c - d)"
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  by simp
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lemma minus_diff_minus:
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  fixes a b :: "'a::ab_group_add"
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  shows "- a - - b = - (a - b)"
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  by simp
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lemma mult_diff_mult:
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  fixes x y a b :: "'a::ring"
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  shows "(x * y - a * b) = x * (y - b) + (x - a) * b"
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  by (simp add: algebra_simps)
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lemma inverse_diff_inverse:
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  fixes a b :: "'a::division_ring"
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  assumes "a \<noteq> 0" and "b \<noteq> 0"
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  shows "inverse a - inverse b = - (inverse a * (a - b) * inverse b)"
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  using assms by (simp add: algebra_simps)
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lemma obtain_pos_sum:
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  fixes r :: rat assumes r: "0 < r"
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  obtains s t where "0 < s" and "0 < t" and "r = s + t"
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proof
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    from r show "0 < r/2" by simp
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    from r show "0 < r/2" by simp
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    show "r = r/2 + r/2" by simp
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qed
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subsection {* Sequences that converge to zero *}
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definition
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  vanishes :: "(nat \<Rightarrow> rat) \<Rightarrow> bool"
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where
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  "vanishes X = (\<forall>r>0. \<exists>k. \<forall>n\<ge>k. \<bar>X n\<bar> < r)"
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lemma vanishesI: "(\<And>r. 0 < r \<Longrightarrow> \<exists>k. \<forall>n\<ge>k. \<bar>X n\<bar> < r) \<Longrightarrow> vanishes X"
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  unfolding vanishes_def by simp
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lemma vanishesD: "\<lbrakk>vanishes X; 0 < r\<rbrakk> \<Longrightarrow> \<exists>k. \<forall>n\<ge>k. \<bar>X n\<bar> < r"
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  unfolding vanishes_def by simp
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lemma vanishes_const [simp]: "vanishes (\<lambda>n. c) \<longleftrightarrow> c = 0"
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  unfolding vanishes_def
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  apply (cases "c = 0", auto)
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  apply (rule exI [where x="\<bar>c\<bar>"], auto)
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  done
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lemma vanishes_minus: "vanishes X \<Longrightarrow> vanishes (\<lambda>n. - X n)"
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  unfolding vanishes_def by simp
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lemma vanishes_add:
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  assumes X: "vanishes X" and Y: "vanishes Y"
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  shows "vanishes (\<lambda>n. X n + Y n)"
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proof (rule vanishesI)
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  fix r :: rat assume "0 < r"
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  then obtain s t where s: "0 < s" and t: "0 < t" and r: "r = s + t"
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    by (rule obtain_pos_sum)
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  obtain i where i: "\<forall>n\<ge>i. \<bar>X n\<bar> < s"
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    using vanishesD [OF X s] ..
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  obtain j where j: "\<forall>n\<ge>j. \<bar>Y n\<bar> < t"
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    using vanishesD [OF Y t] ..
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  have "\<forall>n\<ge>max i j. \<bar>X n + Y n\<bar> < r"
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  proof (clarsimp)
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    fix n assume n: "i \<le> n" "j \<le> n"
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    have "\<bar>X n + Y n\<bar> \<le> \<bar>X n\<bar> + \<bar>Y n\<bar>" by (rule abs_triangle_ineq)
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    also have "\<dots> < s + t" by (simp add: add_strict_mono i j n)
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    finally show "\<bar>X n + Y n\<bar> < r" unfolding r .
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  qed
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  thus "\<exists>k. \<forall>n\<ge>k. \<bar>X n + Y n\<bar> < r" ..
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qed
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lemma vanishes_diff:
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  assumes X: "vanishes X" and Y: "vanishes Y"
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  shows "vanishes (\<lambda>n. X n - Y n)"
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  unfolding diff_conv_add_uminus by (intro vanishes_add vanishes_minus X Y)
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lemma vanishes_mult_bounded:
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  assumes X: "\<exists>a>0. \<forall>n. \<bar>X n\<bar> < a"
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  assumes Y: "vanishes (\<lambda>n. Y n)"
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  shows "vanishes (\<lambda>n. X n * Y n)"
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proof (rule vanishesI)
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  fix r :: rat assume r: "0 < r"
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  obtain a where a: "0 < a" "\<forall>n. \<bar>X n\<bar> < a"
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    using X by fast
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  obtain b where b: "0 < b" "r = a * b"
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  proof
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    show "0 < r / a" using r a by (simp add: divide_pos_pos)
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    show "r = a * (r / a)" using a by simp
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  qed
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  obtain k where k: "\<forall>n\<ge>k. \<bar>Y n\<bar> < b"
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    using vanishesD [OF Y b(1)] ..
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  have "\<forall>n\<ge>k. \<bar>X n * Y n\<bar> < r"
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    by (simp add: b(2) abs_mult mult_strict_mono' a k)
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  thus "\<exists>k. \<forall>n\<ge>k. \<bar>X n * Y n\<bar> < r" ..
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qed
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subsection {* Cauchy sequences *}
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definition
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  cauchy :: "(nat \<Rightarrow> rat) \<Rightarrow> bool"
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where
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  "cauchy X \<longleftrightarrow> (\<forall>r>0. \<exists>k. \<forall>m\<ge>k. \<forall>n\<ge>k. \<bar>X m - X n\<bar> < r)"
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lemma cauchyI:
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  "(\<And>r. 0 < r \<Longrightarrow> \<exists>k. \<forall>m\<ge>k. \<forall>n\<ge>k. \<bar>X m - X n\<bar> < r) \<Longrightarrow> cauchy X"
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  unfolding cauchy_def by simp
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lemma cauchyD:
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  "\<lbrakk>cauchy X; 0 < r\<rbrakk> \<Longrightarrow> \<exists>k. \<forall>m\<ge>k. \<forall>n\<ge>k. \<bar>X m - X n\<bar> < r"
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  unfolding cauchy_def by simp
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lemma cauchy_const [simp]: "cauchy (\<lambda>n. x)"
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  unfolding cauchy_def by simp
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lemma cauchy_add [simp]:
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  assumes X: "cauchy X" and Y: "cauchy Y"
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  shows "cauchy (\<lambda>n. X n + Y n)"
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proof (rule cauchyI)
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  fix r :: rat assume "0 < r"
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  then obtain s t where s: "0 < s" and t: "0 < t" and r: "r = s + t"
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    by (rule obtain_pos_sum)
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  obtain i where i: "\<forall>m\<ge>i. \<forall>n\<ge>i. \<bar>X m - X n\<bar> < s"
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    using cauchyD [OF X s] ..
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  obtain j where j: "\<forall>m\<ge>j. \<forall>n\<ge>j. \<bar>Y m - Y n\<bar> < t"
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    using cauchyD [OF Y t] ..
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  have "\<forall>m\<ge>max i j. \<forall>n\<ge>max i j. \<bar>(X m + Y m) - (X n + Y n)\<bar> < r"
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  proof (clarsimp)
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    fix m n assume *: "i \<le> m" "j \<le> m" "i \<le> n" "j \<le> n"
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    have "\<bar>(X m + Y m) - (X n + Y n)\<bar> \<le> \<bar>X m - X n\<bar> + \<bar>Y m - Y n\<bar>"
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      unfolding add_diff_add by (rule abs_triangle_ineq)
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    also have "\<dots> < s + t"
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      by (rule add_strict_mono, simp_all add: i j *)
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    finally show "\<bar>(X m + Y m) - (X n + Y n)\<bar> < r" unfolding r .
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  qed
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  thus "\<exists>k. \<forall>m\<ge>k. \<forall>n\<ge>k. \<bar>(X m + Y m) - (X n + Y n)\<bar> < r" ..
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qed
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lemma cauchy_minus [simp]:
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  assumes X: "cauchy X"
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  shows "cauchy (\<lambda>n. - X n)"
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using assms unfolding cauchy_def
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unfolding minus_diff_minus abs_minus_cancel .
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lemma cauchy_diff [simp]:
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  assumes X: "cauchy X" and Y: "cauchy Y"
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  shows "cauchy (\<lambda>n. X n - Y n)"
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  using assms unfolding diff_conv_add_uminus by (simp del: add_uminus_conv_diff)
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lemma cauchy_imp_bounded:
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  assumes "cauchy X" shows "\<exists>b>0. \<forall>n. \<bar>X n\<bar> < b"
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proof -
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  obtain k where k: "\<forall>m\<ge>k. \<forall>n\<ge>k. \<bar>X m - X n\<bar> < 1"
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    using cauchyD [OF assms zero_less_one] ..
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  show "\<exists>b>0. \<forall>n. \<bar>X n\<bar> < b"
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  proof (intro exI conjI allI)
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    have "0 \<le> \<bar>X 0\<bar>" by simp
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    also have "\<bar>X 0\<bar> \<le> Max (abs ` X ` {..k})" by simp
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    finally have "0 \<le> Max (abs ` X ` {..k})" .
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    thus "0 < Max (abs ` X ` {..k}) + 1" by simp
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  next
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    fix n :: nat
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    show "\<bar>X n\<bar> < Max (abs ` X ` {..k}) + 1"
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    proof (rule linorder_le_cases)
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      assume "n \<le> k"
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      hence "\<bar>X n\<bar> \<le> Max (abs ` X ` {..k})" by simp
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      thus "\<bar>X n\<bar> < Max (abs ` X ` {..k}) + 1" by simp
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    next
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      assume "k \<le> n"
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      have "\<bar>X n\<bar> = \<bar>X k + (X n - X k)\<bar>" by simp
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      also have "\<bar>X k + (X n - X k)\<bar> \<le> \<bar>X k\<bar> + \<bar>X n - X k\<bar>"
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        by (rule abs_triangle_ineq)
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      also have "\<dots> < Max (abs ` X ` {..k}) + 1"
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        by (rule add_le_less_mono, simp, simp add: k `k \<le> n`)
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      finally show "\<bar>X n\<bar> < Max (abs ` X ` {..k}) + 1" .
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    qed
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  qed
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qed
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lemma cauchy_mult [simp]:
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  assumes X: "cauchy X" and Y: "cauchy Y"
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  shows "cauchy (\<lambda>n. X n * Y n)"
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proof (rule cauchyI)
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  fix r :: rat assume "0 < r"
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  then obtain u v where u: "0 < u" and v: "0 < v" and "r = u + v"
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    by (rule obtain_pos_sum)
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  obtain a where a: "0 < a" "\<forall>n. \<bar>X n\<bar> < a"
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    using cauchy_imp_bounded [OF X] by fast
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  obtain b where b: "0 < b" "\<forall>n. \<bar>Y n\<bar> < b"
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    using cauchy_imp_bounded [OF Y] by fast
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  obtain s t where s: "0 < s" and t: "0 < t" and r: "r = a * t + s * b"
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  proof
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    show "0 < v/b" using v b(1) by (rule divide_pos_pos)
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    show "0 < u/a" using u a(1) by (rule divide_pos_pos)
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    show "r = a * (u/a) + (v/b) * b"
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      using a(1) b(1) `r = u + v` by simp
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  qed
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  obtain i where i: "\<forall>m\<ge>i. \<forall>n\<ge>i. \<bar>X m - X n\<bar> < s"
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    using cauchyD [OF X s] ..
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  obtain j where j: "\<forall>m\<ge>j. \<forall>n\<ge>j. \<bar>Y m - Y n\<bar> < t"
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    using cauchyD [OF Y t] ..
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  have "\<forall>m\<ge>max i j. \<forall>n\<ge>max i j. \<bar>X m * Y m - X n * Y n\<bar> < r"
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  proof (clarsimp)
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    fix m n assume *: "i \<le> m" "j \<le> m" "i \<le> n" "j \<le> n"
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    have "\<bar>X m * Y m - X n * Y n\<bar> = \<bar>X m * (Y m - Y n) + (X m - X n) * Y n\<bar>"
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      unfolding mult_diff_mult ..
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    also have "\<dots> \<le> \<bar>X m * (Y m - Y n)\<bar> + \<bar>(X m - X n) * Y n\<bar>"
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      by (rule abs_triangle_ineq)
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    also have "\<dots> = \<bar>X m\<bar> * \<bar>Y m - Y n\<bar> + \<bar>X m - X n\<bar> * \<bar>Y n\<bar>"
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      unfolding abs_mult ..
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    also have "\<dots> < a * t + s * b"
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      by (simp_all add: add_strict_mono mult_strict_mono' a b i j *)
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    finally show "\<bar>X m * Y m - X n * Y n\<bar> < r" unfolding r .
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  qed
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  thus "\<exists>k. \<forall>m\<ge>k. \<forall>n\<ge>k. \<bar>X m * Y m - X n * Y n\<bar> < r" ..
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qed
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lemma cauchy_not_vanishes_cases:
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  assumes X: "cauchy X"
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  assumes nz: "\<not> vanishes X"
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  shows "\<exists>b>0. \<exists>k. (\<forall>n\<ge>k. b < - X n) \<or> (\<forall>n\<ge>k. b < X n)"
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proof -
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  obtain r where "0 < r" and r: "\<forall>k. \<exists>n\<ge>k. r \<le> \<bar>X n\<bar>"
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    using nz unfolding vanishes_def by (auto simp add: not_less)
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  obtain s t where s: "0 < s" and t: "0 < t" and "r = s + t"
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    using `0 < r` by (rule obtain_pos_sum)
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  obtain i where i: "\<forall>m\<ge>i. \<forall>n\<ge>i. \<bar>X m - X n\<bar> < s"
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    using cauchyD [OF X s] ..
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  obtain k where "i \<le> k" and "r \<le> \<bar>X k\<bar>"
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    using r by fast
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  have k: "\<forall>n\<ge>k. \<bar>X n - X k\<bar> < s"
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    using i `i \<le> k` by auto
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  have "X k \<le> - r \<or> r \<le> X k"
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    using `r \<le> \<bar>X k\<bar>` by auto
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  hence "(\<forall>n\<ge>k. t < - X n) \<or> (\<forall>n\<ge>k. t < X n)"
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    unfolding `r = s + t` using k by auto
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  hence "\<exists>k. (\<forall>n\<ge>k. t < - X n) \<or> (\<forall>n\<ge>k. t < X n)" ..
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   263
  thus "\<exists>t>0. \<exists>k. (\<forall>n\<ge>k. t < - X n) \<or> (\<forall>n\<ge>k. t < X n)"
hoelzl@51523
   264
    using t by auto
hoelzl@51523
   265
qed
hoelzl@51523
   266
hoelzl@51523
   267
lemma cauchy_not_vanishes:
hoelzl@51523
   268
  assumes X: "cauchy X"
hoelzl@51523
   269
  assumes nz: "\<not> vanishes X"
hoelzl@51523
   270
  shows "\<exists>b>0. \<exists>k. \<forall>n\<ge>k. b < \<bar>X n\<bar>"
hoelzl@51523
   271
using cauchy_not_vanishes_cases [OF assms]
hoelzl@51523
   272
by clarify (rule exI, erule conjI, rule_tac x=k in exI, auto)
hoelzl@51523
   273
hoelzl@51523
   274
lemma cauchy_inverse [simp]:
hoelzl@51523
   275
  assumes X: "cauchy X"
hoelzl@51523
   276
  assumes nz: "\<not> vanishes X"
hoelzl@51523
   277
  shows "cauchy (\<lambda>n. inverse (X n))"
hoelzl@51523
   278
proof (rule cauchyI)
hoelzl@51523
   279
  fix r :: rat assume "0 < r"
hoelzl@51523
   280
  obtain b i where b: "0 < b" and i: "\<forall>n\<ge>i. b < \<bar>X n\<bar>"
hoelzl@51523
   281
    using cauchy_not_vanishes [OF X nz] by fast
hoelzl@51523
   282
  from b i have nz: "\<forall>n\<ge>i. X n \<noteq> 0" by auto
hoelzl@51523
   283
  obtain s where s: "0 < s" and r: "r = inverse b * s * inverse b"
hoelzl@51523
   284
  proof
hoelzl@51523
   285
    show "0 < b * r * b"
hoelzl@51523
   286
      by (simp add: `0 < r` b mult_pos_pos)
hoelzl@51523
   287
    show "r = inverse b * (b * r * b) * inverse b"
hoelzl@51523
   288
      using b by simp
hoelzl@51523
   289
  qed
hoelzl@51523
   290
  obtain j where j: "\<forall>m\<ge>j. \<forall>n\<ge>j. \<bar>X m - X n\<bar> < s"
hoelzl@51523
   291
    using cauchyD [OF X s] ..
hoelzl@51523
   292
  have "\<forall>m\<ge>max i j. \<forall>n\<ge>max i j. \<bar>inverse (X m) - inverse (X n)\<bar> < r"
hoelzl@51523
   293
  proof (clarsimp)
hoelzl@51523
   294
    fix m n assume *: "i \<le> m" "j \<le> m" "i \<le> n" "j \<le> n"
hoelzl@51523
   295
    have "\<bar>inverse (X m) - inverse (X n)\<bar> =
hoelzl@51523
   296
          inverse \<bar>X m\<bar> * \<bar>X m - X n\<bar> * inverse \<bar>X n\<bar>"
hoelzl@51523
   297
      by (simp add: inverse_diff_inverse nz * abs_mult)
hoelzl@51523
   298
    also have "\<dots> < inverse b * s * inverse b"
hoelzl@51523
   299
      by (simp add: mult_strict_mono less_imp_inverse_less
hoelzl@51523
   300
                    mult_pos_pos i j b * s)
hoelzl@51523
   301
    finally show "\<bar>inverse (X m) - inverse (X n)\<bar> < r" unfolding r .
hoelzl@51523
   302
  qed
hoelzl@51523
   303
  thus "\<exists>k. \<forall>m\<ge>k. \<forall>n\<ge>k. \<bar>inverse (X m) - inverse (X n)\<bar> < r" ..
hoelzl@51523
   304
qed
hoelzl@51523
   305
hoelzl@51523
   306
lemma vanishes_diff_inverse:
hoelzl@51523
   307
  assumes X: "cauchy X" "\<not> vanishes X"
hoelzl@51523
   308
  assumes Y: "cauchy Y" "\<not> vanishes Y"
hoelzl@51523
   309
  assumes XY: "vanishes (\<lambda>n. X n - Y n)"
hoelzl@51523
   310
  shows "vanishes (\<lambda>n. inverse (X n) - inverse (Y n))"
hoelzl@51523
   311
proof (rule vanishesI)
hoelzl@51523
   312
  fix r :: rat assume r: "0 < r"
hoelzl@51523
   313
  obtain a i where a: "0 < a" and i: "\<forall>n\<ge>i. a < \<bar>X n\<bar>"
hoelzl@51523
   314
    using cauchy_not_vanishes [OF X] by fast
hoelzl@51523
   315
  obtain b j where b: "0 < b" and j: "\<forall>n\<ge>j. b < \<bar>Y n\<bar>"
hoelzl@51523
   316
    using cauchy_not_vanishes [OF Y] by fast
hoelzl@51523
   317
  obtain s where s: "0 < s" and "inverse a * s * inverse b = r"
hoelzl@51523
   318
  proof
hoelzl@51523
   319
    show "0 < a * r * b"
hoelzl@51523
   320
      using a r b by (simp add: mult_pos_pos)
hoelzl@51523
   321
    show "inverse a * (a * r * b) * inverse b = r"
hoelzl@51523
   322
      using a r b by simp
hoelzl@51523
   323
  qed
hoelzl@51523
   324
  obtain k where k: "\<forall>n\<ge>k. \<bar>X n - Y n\<bar> < s"
hoelzl@51523
   325
    using vanishesD [OF XY s] ..
hoelzl@51523
   326
  have "\<forall>n\<ge>max (max i j) k. \<bar>inverse (X n) - inverse (Y n)\<bar> < r"
hoelzl@51523
   327
  proof (clarsimp)
hoelzl@51523
   328
    fix n assume n: "i \<le> n" "j \<le> n" "k \<le> n"
hoelzl@51523
   329
    have "X n \<noteq> 0" and "Y n \<noteq> 0"
hoelzl@51523
   330
      using i j a b n by auto
hoelzl@51523
   331
    hence "\<bar>inverse (X n) - inverse (Y n)\<bar> =
hoelzl@51523
   332
        inverse \<bar>X n\<bar> * \<bar>X n - Y n\<bar> * inverse \<bar>Y n\<bar>"
hoelzl@51523
   333
      by (simp add: inverse_diff_inverse abs_mult)
hoelzl@51523
   334
    also have "\<dots> < inverse a * s * inverse b"
hoelzl@51523
   335
      apply (intro mult_strict_mono' less_imp_inverse_less)
hoelzl@51523
   336
      apply (simp_all add: a b i j k n mult_nonneg_nonneg)
hoelzl@51523
   337
      done
hoelzl@51523
   338
    also note `inverse a * s * inverse b = r`
hoelzl@51523
   339
    finally show "\<bar>inverse (X n) - inverse (Y n)\<bar> < r" .
hoelzl@51523
   340
  qed
hoelzl@51523
   341
  thus "\<exists>k. \<forall>n\<ge>k. \<bar>inverse (X n) - inverse (Y n)\<bar> < r" ..
hoelzl@51523
   342
qed
hoelzl@51523
   343
hoelzl@51523
   344
subsection {* Equivalence relation on Cauchy sequences *}
hoelzl@51523
   345
hoelzl@51523
   346
definition realrel :: "(nat \<Rightarrow> rat) \<Rightarrow> (nat \<Rightarrow> rat) \<Rightarrow> bool"
hoelzl@51523
   347
  where "realrel = (\<lambda>X Y. cauchy X \<and> cauchy Y \<and> vanishes (\<lambda>n. X n - Y n))"
hoelzl@51523
   348
hoelzl@51523
   349
lemma realrelI [intro?]:
hoelzl@51523
   350
  assumes "cauchy X" and "cauchy Y" and "vanishes (\<lambda>n. X n - Y n)"
hoelzl@51523
   351
  shows "realrel X Y"
hoelzl@51523
   352
  using assms unfolding realrel_def by simp
hoelzl@51523
   353
hoelzl@51523
   354
lemma realrel_refl: "cauchy X \<Longrightarrow> realrel X X"
hoelzl@51523
   355
  unfolding realrel_def by simp
hoelzl@51523
   356
hoelzl@51523
   357
lemma symp_realrel: "symp realrel"
hoelzl@51523
   358
  unfolding realrel_def
hoelzl@51523
   359
  by (rule sympI, clarify, drule vanishes_minus, simp)
hoelzl@51523
   360
hoelzl@51523
   361
lemma transp_realrel: "transp realrel"
hoelzl@51523
   362
  unfolding realrel_def
hoelzl@51523
   363
  apply (rule transpI, clarify)
hoelzl@51523
   364
  apply (drule (1) vanishes_add)
hoelzl@51523
   365
  apply (simp add: algebra_simps)
hoelzl@51523
   366
  done
hoelzl@51523
   367
hoelzl@51523
   368
lemma part_equivp_realrel: "part_equivp realrel"
hoelzl@51523
   369
  by (fast intro: part_equivpI symp_realrel transp_realrel
hoelzl@51523
   370
    realrel_refl cauchy_const)
hoelzl@51523
   371
hoelzl@51523
   372
subsection {* The field of real numbers *}
hoelzl@51523
   373
hoelzl@51523
   374
quotient_type real = "nat \<Rightarrow> rat" / partial: realrel
hoelzl@51523
   375
  morphisms rep_real Real
hoelzl@51523
   376
  by (rule part_equivp_realrel)
hoelzl@51523
   377
hoelzl@51523
   378
lemma cr_real_eq: "pcr_real = (\<lambda>x y. cauchy x \<and> Real x = y)"
hoelzl@51523
   379
  unfolding real.pcr_cr_eq cr_real_def realrel_def by auto
hoelzl@51523
   380
hoelzl@51523
   381
lemma Real_induct [induct type: real]: (* TODO: generate automatically *)
hoelzl@51523
   382
  assumes "\<And>X. cauchy X \<Longrightarrow> P (Real X)" shows "P x"
hoelzl@51523
   383
proof (induct x)
hoelzl@51523
   384
  case (1 X)
hoelzl@51523
   385
  hence "cauchy X" by (simp add: realrel_def)
hoelzl@51523
   386
  thus "P (Real X)" by (rule assms)
hoelzl@51523
   387
qed
hoelzl@51523
   388
hoelzl@51523
   389
lemma eq_Real:
hoelzl@51523
   390
  "cauchy X \<Longrightarrow> cauchy Y \<Longrightarrow> Real X = Real Y \<longleftrightarrow> vanishes (\<lambda>n. X n - Y n)"
hoelzl@51523
   391
  using real.rel_eq_transfer
hoelzl@51523
   392
  unfolding real.pcr_cr_eq cr_real_def fun_rel_def realrel_def by simp
hoelzl@51523
   393
kuncar@51956
   394
lemma Domainp_pcr_real [transfer_domain_rule]: "Domainp pcr_real = cauchy"
kuncar@51956
   395
by (simp add: real.domain_eq realrel_def)
hoelzl@51523
   396
hoelzl@51523
   397
instantiation real :: field_inverse_zero
hoelzl@51523
   398
begin
hoelzl@51523
   399
hoelzl@51523
   400
lift_definition zero_real :: "real" is "\<lambda>n. 0"
hoelzl@51523
   401
  by (simp add: realrel_refl)
hoelzl@51523
   402
hoelzl@51523
   403
lift_definition one_real :: "real" is "\<lambda>n. 1"
hoelzl@51523
   404
  by (simp add: realrel_refl)
hoelzl@51523
   405
hoelzl@51523
   406
lift_definition plus_real :: "real \<Rightarrow> real \<Rightarrow> real" is "\<lambda>X Y n. X n + Y n"
hoelzl@51523
   407
  unfolding realrel_def add_diff_add
hoelzl@51523
   408
  by (simp only: cauchy_add vanishes_add simp_thms)
hoelzl@51523
   409
hoelzl@51523
   410
lift_definition uminus_real :: "real \<Rightarrow> real" is "\<lambda>X n. - X n"
hoelzl@51523
   411
  unfolding realrel_def minus_diff_minus
hoelzl@51523
   412
  by (simp only: cauchy_minus vanishes_minus simp_thms)
hoelzl@51523
   413
hoelzl@51523
   414
lift_definition times_real :: "real \<Rightarrow> real \<Rightarrow> real" is "\<lambda>X Y n. X n * Y n"
hoelzl@51523
   415
  unfolding realrel_def mult_diff_mult
hoelzl@51523
   416
  by (subst (4) mult_commute, simp only: cauchy_mult vanishes_add
hoelzl@51523
   417
    vanishes_mult_bounded cauchy_imp_bounded simp_thms)
hoelzl@51523
   418
hoelzl@51523
   419
lift_definition inverse_real :: "real \<Rightarrow> real"
hoelzl@51523
   420
  is "\<lambda>X. if vanishes X then (\<lambda>n. 0) else (\<lambda>n. inverse (X n))"
hoelzl@51523
   421
proof -
hoelzl@51523
   422
  fix X Y assume "realrel X Y"
hoelzl@51523
   423
  hence X: "cauchy X" and Y: "cauchy Y" and XY: "vanishes (\<lambda>n. X n - Y n)"
hoelzl@51523
   424
    unfolding realrel_def by simp_all
hoelzl@51523
   425
  have "vanishes X \<longleftrightarrow> vanishes Y"
hoelzl@51523
   426
  proof
hoelzl@51523
   427
    assume "vanishes X"
hoelzl@51523
   428
    from vanishes_diff [OF this XY] show "vanishes Y" by simp
hoelzl@51523
   429
  next
hoelzl@51523
   430
    assume "vanishes Y"
hoelzl@51523
   431
    from vanishes_add [OF this XY] show "vanishes X" by simp
hoelzl@51523
   432
  qed
hoelzl@51523
   433
  thus "?thesis X Y"
hoelzl@51523
   434
    unfolding realrel_def
hoelzl@51523
   435
    by (simp add: vanishes_diff_inverse X Y XY)
hoelzl@51523
   436
qed
hoelzl@51523
   437
hoelzl@51523
   438
definition
hoelzl@51523
   439
  "x - y = (x::real) + - y"
hoelzl@51523
   440
hoelzl@51523
   441
definition
hoelzl@51523
   442
  "x / y = (x::real) * inverse y"
hoelzl@51523
   443
hoelzl@51523
   444
lemma add_Real:
hoelzl@51523
   445
  assumes X: "cauchy X" and Y: "cauchy Y"
hoelzl@51523
   446
  shows "Real X + Real Y = Real (\<lambda>n. X n + Y n)"
hoelzl@51523
   447
  using assms plus_real.transfer
hoelzl@51523
   448
  unfolding cr_real_eq fun_rel_def by simp
hoelzl@51523
   449
hoelzl@51523
   450
lemma minus_Real:
hoelzl@51523
   451
  assumes X: "cauchy X"
hoelzl@51523
   452
  shows "- Real X = Real (\<lambda>n. - X n)"
hoelzl@51523
   453
  using assms uminus_real.transfer
hoelzl@51523
   454
  unfolding cr_real_eq fun_rel_def by simp
hoelzl@51523
   455
hoelzl@51523
   456
lemma diff_Real:
hoelzl@51523
   457
  assumes X: "cauchy X" and Y: "cauchy Y"
hoelzl@51523
   458
  shows "Real X - Real Y = Real (\<lambda>n. X n - Y n)"
haftmann@54230
   459
  unfolding minus_real_def
hoelzl@51523
   460
  by (simp add: minus_Real add_Real X Y)
hoelzl@51523
   461
hoelzl@51523
   462
lemma mult_Real:
hoelzl@51523
   463
  assumes X: "cauchy X" and Y: "cauchy Y"
hoelzl@51523
   464
  shows "Real X * Real Y = Real (\<lambda>n. X n * Y n)"
hoelzl@51523
   465
  using assms times_real.transfer
hoelzl@51523
   466
  unfolding cr_real_eq fun_rel_def by simp
hoelzl@51523
   467
hoelzl@51523
   468
lemma inverse_Real:
hoelzl@51523
   469
  assumes X: "cauchy X"
hoelzl@51523
   470
  shows "inverse (Real X) =
hoelzl@51523
   471
    (if vanishes X then 0 else Real (\<lambda>n. inverse (X n)))"
hoelzl@51523
   472
  using assms inverse_real.transfer zero_real.transfer
hoelzl@51523
   473
  unfolding cr_real_eq fun_rel_def by (simp split: split_if_asm, metis)
hoelzl@51523
   474
hoelzl@51523
   475
instance proof
hoelzl@51523
   476
  fix a b c :: real
hoelzl@51523
   477
  show "a + b = b + a"
hoelzl@51523
   478
    by transfer (simp add: add_ac realrel_def)
hoelzl@51523
   479
  show "(a + b) + c = a + (b + c)"
hoelzl@51523
   480
    by transfer (simp add: add_ac realrel_def)
hoelzl@51523
   481
  show "0 + a = a"
hoelzl@51523
   482
    by transfer (simp add: realrel_def)
hoelzl@51523
   483
  show "- a + a = 0"
hoelzl@51523
   484
    by transfer (simp add: realrel_def)
hoelzl@51523
   485
  show "a - b = a + - b"
hoelzl@51523
   486
    by (rule minus_real_def)
hoelzl@51523
   487
  show "(a * b) * c = a * (b * c)"
hoelzl@51523
   488
    by transfer (simp add: mult_ac realrel_def)
hoelzl@51523
   489
  show "a * b = b * a"
hoelzl@51523
   490
    by transfer (simp add: mult_ac realrel_def)
hoelzl@51523
   491
  show "1 * a = a"
hoelzl@51523
   492
    by transfer (simp add: mult_ac realrel_def)
hoelzl@51523
   493
  show "(a + b) * c = a * c + b * c"
hoelzl@51523
   494
    by transfer (simp add: distrib_right realrel_def)
hoelzl@51523
   495
  show "(0\<Colon>real) \<noteq> (1\<Colon>real)"
hoelzl@51523
   496
    by transfer (simp add: realrel_def)
hoelzl@51523
   497
  show "a \<noteq> 0 \<Longrightarrow> inverse a * a = 1"
hoelzl@51523
   498
    apply transfer
hoelzl@51523
   499
    apply (simp add: realrel_def)
hoelzl@51523
   500
    apply (rule vanishesI)
hoelzl@51523
   501
    apply (frule (1) cauchy_not_vanishes, clarify)
hoelzl@51523
   502
    apply (rule_tac x=k in exI, clarify)
hoelzl@51523
   503
    apply (drule_tac x=n in spec, simp)
hoelzl@51523
   504
    done
hoelzl@51523
   505
  show "a / b = a * inverse b"
hoelzl@51523
   506
    by (rule divide_real_def)
hoelzl@51523
   507
  show "inverse (0::real) = 0"
hoelzl@51523
   508
    by transfer (simp add: realrel_def)
hoelzl@51523
   509
qed
hoelzl@51523
   510
hoelzl@51523
   511
end
hoelzl@51523
   512
hoelzl@51523
   513
subsection {* Positive reals *}
hoelzl@51523
   514
hoelzl@51523
   515
lift_definition positive :: "real \<Rightarrow> bool"
hoelzl@51523
   516
  is "\<lambda>X. \<exists>r>0. \<exists>k. \<forall>n\<ge>k. r < X n"
hoelzl@51523
   517
proof -
hoelzl@51523
   518
  { fix X Y
hoelzl@51523
   519
    assume "realrel X Y"
hoelzl@51523
   520
    hence XY: "vanishes (\<lambda>n. X n - Y n)"
hoelzl@51523
   521
      unfolding realrel_def by simp_all
hoelzl@51523
   522
    assume "\<exists>r>0. \<exists>k. \<forall>n\<ge>k. r < X n"
hoelzl@51523
   523
    then obtain r i where "0 < r" and i: "\<forall>n\<ge>i. r < X n"
hoelzl@51523
   524
      by fast
hoelzl@51523
   525
    obtain s t where s: "0 < s" and t: "0 < t" and r: "r = s + t"
hoelzl@51523
   526
      using `0 < r` by (rule obtain_pos_sum)
hoelzl@51523
   527
    obtain j where j: "\<forall>n\<ge>j. \<bar>X n - Y n\<bar> < s"
hoelzl@51523
   528
      using vanishesD [OF XY s] ..
hoelzl@51523
   529
    have "\<forall>n\<ge>max i j. t < Y n"
hoelzl@51523
   530
    proof (clarsimp)
hoelzl@51523
   531
      fix n assume n: "i \<le> n" "j \<le> n"
hoelzl@51523
   532
      have "\<bar>X n - Y n\<bar> < s" and "r < X n"
hoelzl@51523
   533
        using i j n by simp_all
hoelzl@51523
   534
      thus "t < Y n" unfolding r by simp
hoelzl@51523
   535
    qed
hoelzl@51523
   536
    hence "\<exists>r>0. \<exists>k. \<forall>n\<ge>k. r < Y n" using t by fast
hoelzl@51523
   537
  } note 1 = this
hoelzl@51523
   538
  fix X Y assume "realrel X Y"
hoelzl@51523
   539
  hence "realrel X Y" and "realrel Y X"
hoelzl@51523
   540
    using symp_realrel unfolding symp_def by auto
hoelzl@51523
   541
  thus "?thesis X Y"
hoelzl@51523
   542
    by (safe elim!: 1)
hoelzl@51523
   543
qed
hoelzl@51523
   544
hoelzl@51523
   545
lemma positive_Real:
hoelzl@51523
   546
  assumes X: "cauchy X"
hoelzl@51523
   547
  shows "positive (Real X) \<longleftrightarrow> (\<exists>r>0. \<exists>k. \<forall>n\<ge>k. r < X n)"
hoelzl@51523
   548
  using assms positive.transfer
hoelzl@51523
   549
  unfolding cr_real_eq fun_rel_def by simp
hoelzl@51523
   550
hoelzl@51523
   551
lemma positive_zero: "\<not> positive 0"
hoelzl@51523
   552
  by transfer auto
hoelzl@51523
   553
hoelzl@51523
   554
lemma positive_add:
hoelzl@51523
   555
  "positive x \<Longrightarrow> positive y \<Longrightarrow> positive (x + y)"
hoelzl@51523
   556
apply transfer
hoelzl@51523
   557
apply (clarify, rename_tac a b i j)
hoelzl@51523
   558
apply (rule_tac x="a + b" in exI, simp)
hoelzl@51523
   559
apply (rule_tac x="max i j" in exI, clarsimp)
hoelzl@51523
   560
apply (simp add: add_strict_mono)
hoelzl@51523
   561
done
hoelzl@51523
   562
hoelzl@51523
   563
lemma positive_mult:
hoelzl@51523
   564
  "positive x \<Longrightarrow> positive y \<Longrightarrow> positive (x * y)"
hoelzl@51523
   565
apply transfer
hoelzl@51523
   566
apply (clarify, rename_tac a b i j)
hoelzl@51523
   567
apply (rule_tac x="a * b" in exI, simp add: mult_pos_pos)
hoelzl@51523
   568
apply (rule_tac x="max i j" in exI, clarsimp)
hoelzl@51523
   569
apply (rule mult_strict_mono, auto)
hoelzl@51523
   570
done
hoelzl@51523
   571
hoelzl@51523
   572
lemma positive_minus:
hoelzl@51523
   573
  "\<not> positive x \<Longrightarrow> x \<noteq> 0 \<Longrightarrow> positive (- x)"
hoelzl@51523
   574
apply transfer
hoelzl@51523
   575
apply (simp add: realrel_def)
hoelzl@51523
   576
apply (drule (1) cauchy_not_vanishes_cases, safe, fast, fast)
hoelzl@51523
   577
done
hoelzl@51523
   578
hoelzl@51523
   579
instantiation real :: linordered_field_inverse_zero
hoelzl@51523
   580
begin
hoelzl@51523
   581
hoelzl@51523
   582
definition
hoelzl@51523
   583
  "x < y \<longleftrightarrow> positive (y - x)"
hoelzl@51523
   584
hoelzl@51523
   585
definition
hoelzl@51523
   586
  "x \<le> (y::real) \<longleftrightarrow> x < y \<or> x = y"
hoelzl@51523
   587
hoelzl@51523
   588
definition
hoelzl@51523
   589
  "abs (a::real) = (if a < 0 then - a else a)"
hoelzl@51523
   590
hoelzl@51523
   591
definition
hoelzl@51523
   592
  "sgn (a::real) = (if a = 0 then 0 else if 0 < a then 1 else - 1)"
hoelzl@51523
   593
hoelzl@51523
   594
instance proof
hoelzl@51523
   595
  fix a b c :: real
hoelzl@51523
   596
  show "\<bar>a\<bar> = (if a < 0 then - a else a)"
hoelzl@51523
   597
    by (rule abs_real_def)
hoelzl@51523
   598
  show "a < b \<longleftrightarrow> a \<le> b \<and> \<not> b \<le> a"
hoelzl@51523
   599
    unfolding less_eq_real_def less_real_def
hoelzl@51523
   600
    by (auto, drule (1) positive_add, simp_all add: positive_zero)
hoelzl@51523
   601
  show "a \<le> a"
hoelzl@51523
   602
    unfolding less_eq_real_def by simp
hoelzl@51523
   603
  show "a \<le> b \<Longrightarrow> b \<le> c \<Longrightarrow> a \<le> c"
hoelzl@51523
   604
    unfolding less_eq_real_def less_real_def
hoelzl@51523
   605
    by (auto, drule (1) positive_add, simp add: algebra_simps)
hoelzl@51523
   606
  show "a \<le> b \<Longrightarrow> b \<le> a \<Longrightarrow> a = b"
hoelzl@51523
   607
    unfolding less_eq_real_def less_real_def
hoelzl@51523
   608
    by (auto, drule (1) positive_add, simp add: positive_zero)
hoelzl@51523
   609
  show "a \<le> b \<Longrightarrow> c + a \<le> c + b"
haftmann@54230
   610
    unfolding less_eq_real_def less_real_def by auto
hoelzl@51523
   611
    (* FIXME: Procedure int_combine_numerals: c + b - (c + a) \<equiv> b + - a *)
hoelzl@51523
   612
    (* Should produce c + b - (c + a) \<equiv> b - a *)
hoelzl@51523
   613
  show "sgn a = (if a = 0 then 0 else if 0 < a then 1 else - 1)"
hoelzl@51523
   614
    by (rule sgn_real_def)
hoelzl@51523
   615
  show "a \<le> b \<or> b \<le> a"
hoelzl@51523
   616
    unfolding less_eq_real_def less_real_def
hoelzl@51523
   617
    by (auto dest!: positive_minus)
hoelzl@51523
   618
  show "a < b \<Longrightarrow> 0 < c \<Longrightarrow> c * a < c * b"
hoelzl@51523
   619
    unfolding less_real_def
hoelzl@51523
   620
    by (drule (1) positive_mult, simp add: algebra_simps)
hoelzl@51523
   621
qed
hoelzl@51523
   622
hoelzl@51523
   623
end
hoelzl@51523
   624
hoelzl@51523
   625
instantiation real :: distrib_lattice
hoelzl@51523
   626
begin
hoelzl@51523
   627
hoelzl@51523
   628
definition
hoelzl@51523
   629
  "(inf :: real \<Rightarrow> real \<Rightarrow> real) = min"
hoelzl@51523
   630
hoelzl@51523
   631
definition
hoelzl@51523
   632
  "(sup :: real \<Rightarrow> real \<Rightarrow> real) = max"
hoelzl@51523
   633
hoelzl@51523
   634
instance proof
hoelzl@51523
   635
qed (auto simp add: inf_real_def sup_real_def min_max.sup_inf_distrib1)
hoelzl@51523
   636
hoelzl@51523
   637
end
hoelzl@51523
   638
hoelzl@51523
   639
lemma of_nat_Real: "of_nat x = Real (\<lambda>n. of_nat x)"
hoelzl@51523
   640
apply (induct x)
hoelzl@51523
   641
apply (simp add: zero_real_def)
hoelzl@51523
   642
apply (simp add: one_real_def add_Real)
hoelzl@51523
   643
done
hoelzl@51523
   644
hoelzl@51523
   645
lemma of_int_Real: "of_int x = Real (\<lambda>n. of_int x)"
hoelzl@51523
   646
apply (cases x rule: int_diff_cases)
hoelzl@51523
   647
apply (simp add: of_nat_Real diff_Real)
hoelzl@51523
   648
done
hoelzl@51523
   649
hoelzl@51523
   650
lemma of_rat_Real: "of_rat x = Real (\<lambda>n. x)"
hoelzl@51523
   651
apply (induct x)
hoelzl@51523
   652
apply (simp add: Fract_of_int_quotient of_rat_divide)
hoelzl@51523
   653
apply (simp add: of_int_Real divide_inverse)
hoelzl@51523
   654
apply (simp add: inverse_Real mult_Real)
hoelzl@51523
   655
done
hoelzl@51523
   656
hoelzl@51523
   657
instance real :: archimedean_field
hoelzl@51523
   658
proof
hoelzl@51523
   659
  fix x :: real
hoelzl@51523
   660
  show "\<exists>z. x \<le> of_int z"
hoelzl@51523
   661
    apply (induct x)
hoelzl@51523
   662
    apply (frule cauchy_imp_bounded, clarify)
hoelzl@51523
   663
    apply (rule_tac x="ceiling b + 1" in exI)
hoelzl@51523
   664
    apply (rule less_imp_le)
hoelzl@51523
   665
    apply (simp add: of_int_Real less_real_def diff_Real positive_Real)
hoelzl@51523
   666
    apply (rule_tac x=1 in exI, simp add: algebra_simps)
hoelzl@51523
   667
    apply (rule_tac x=0 in exI, clarsimp)
hoelzl@51523
   668
    apply (rule le_less_trans [OF abs_ge_self])
hoelzl@51523
   669
    apply (rule less_le_trans [OF _ le_of_int_ceiling])
hoelzl@51523
   670
    apply simp
hoelzl@51523
   671
    done
hoelzl@51523
   672
qed
hoelzl@51523
   673
hoelzl@51523
   674
instantiation real :: floor_ceiling
hoelzl@51523
   675
begin
hoelzl@51523
   676
hoelzl@51523
   677
definition [code del]:
hoelzl@51523
   678
  "floor (x::real) = (THE z. of_int z \<le> x \<and> x < of_int (z + 1))"
hoelzl@51523
   679
hoelzl@51523
   680
instance proof
hoelzl@51523
   681
  fix x :: real
hoelzl@51523
   682
  show "of_int (floor x) \<le> x \<and> x < of_int (floor x + 1)"
hoelzl@51523
   683
    unfolding floor_real_def using floor_exists1 by (rule theI')
hoelzl@51523
   684
qed
hoelzl@51523
   685
hoelzl@51523
   686
end
hoelzl@51523
   687
hoelzl@51523
   688
subsection {* Completeness *}
hoelzl@51523
   689
hoelzl@51523
   690
lemma not_positive_Real:
hoelzl@51523
   691
  assumes X: "cauchy X"
hoelzl@51523
   692
  shows "\<not> positive (Real X) \<longleftrightarrow> (\<forall>r>0. \<exists>k. \<forall>n\<ge>k. X n \<le> r)"
hoelzl@51523
   693
unfolding positive_Real [OF X]
hoelzl@51523
   694
apply (auto, unfold not_less)
hoelzl@51523
   695
apply (erule obtain_pos_sum)
hoelzl@51523
   696
apply (drule_tac x=s in spec, simp)
hoelzl@51523
   697
apply (drule_tac r=t in cauchyD [OF X], clarify)
hoelzl@51523
   698
apply (drule_tac x=k in spec, clarsimp)
hoelzl@51523
   699
apply (rule_tac x=n in exI, clarify, rename_tac m)
hoelzl@51523
   700
apply (drule_tac x=m in spec, simp)
hoelzl@51523
   701
apply (drule_tac x=n in spec, simp)
hoelzl@51523
   702
apply (drule spec, drule (1) mp, clarify, rename_tac i)
hoelzl@51523
   703
apply (rule_tac x="max i k" in exI, simp)
hoelzl@51523
   704
done
hoelzl@51523
   705
hoelzl@51523
   706
lemma le_Real:
hoelzl@51523
   707
  assumes X: "cauchy X" and Y: "cauchy Y"
hoelzl@51523
   708
  shows "Real X \<le> Real Y = (\<forall>r>0. \<exists>k. \<forall>n\<ge>k. X n \<le> Y n + r)"
hoelzl@51523
   709
unfolding not_less [symmetric, where 'a=real] less_real_def
hoelzl@51523
   710
apply (simp add: diff_Real not_positive_Real X Y)
hoelzl@51523
   711
apply (simp add: diff_le_eq add_ac)
hoelzl@51523
   712
done
hoelzl@51523
   713
hoelzl@51523
   714
lemma le_RealI:
hoelzl@51523
   715
  assumes Y: "cauchy Y"
hoelzl@51523
   716
  shows "\<forall>n. x \<le> of_rat (Y n) \<Longrightarrow> x \<le> Real Y"
hoelzl@51523
   717
proof (induct x)
hoelzl@51523
   718
  fix X assume X: "cauchy X" and "\<forall>n. Real X \<le> of_rat (Y n)"
hoelzl@51523
   719
  hence le: "\<And>m r. 0 < r \<Longrightarrow> \<exists>k. \<forall>n\<ge>k. X n \<le> Y m + r"
hoelzl@51523
   720
    by (simp add: of_rat_Real le_Real)
hoelzl@51523
   721
  {
hoelzl@51523
   722
    fix r :: rat assume "0 < r"
hoelzl@51523
   723
    then obtain s t where s: "0 < s" and t: "0 < t" and r: "r = s + t"
hoelzl@51523
   724
      by (rule obtain_pos_sum)
hoelzl@51523
   725
    obtain i where i: "\<forall>m\<ge>i. \<forall>n\<ge>i. \<bar>Y m - Y n\<bar> < s"
hoelzl@51523
   726
      using cauchyD [OF Y s] ..
hoelzl@51523
   727
    obtain j where j: "\<forall>n\<ge>j. X n \<le> Y i + t"
hoelzl@51523
   728
      using le [OF t] ..
hoelzl@51523
   729
    have "\<forall>n\<ge>max i j. X n \<le> Y n + r"
hoelzl@51523
   730
    proof (clarsimp)
hoelzl@51523
   731
      fix n assume n: "i \<le> n" "j \<le> n"
hoelzl@51523
   732
      have "X n \<le> Y i + t" using n j by simp
hoelzl@51523
   733
      moreover have "\<bar>Y i - Y n\<bar> < s" using n i by simp
hoelzl@51523
   734
      ultimately show "X n \<le> Y n + r" unfolding r by simp
hoelzl@51523
   735
    qed
hoelzl@51523
   736
    hence "\<exists>k. \<forall>n\<ge>k. X n \<le> Y n + r" ..
hoelzl@51523
   737
  }
hoelzl@51523
   738
  thus "Real X \<le> Real Y"
hoelzl@51523
   739
    by (simp add: of_rat_Real le_Real X Y)
hoelzl@51523
   740
qed
hoelzl@51523
   741
hoelzl@51523
   742
lemma Real_leI:
hoelzl@51523
   743
  assumes X: "cauchy X"
hoelzl@51523
   744
  assumes le: "\<forall>n. of_rat (X n) \<le> y"
hoelzl@51523
   745
  shows "Real X \<le> y"
hoelzl@51523
   746
proof -
hoelzl@51523
   747
  have "- y \<le> - Real X"
hoelzl@51523
   748
    by (simp add: minus_Real X le_RealI of_rat_minus le)
hoelzl@51523
   749
  thus ?thesis by simp
hoelzl@51523
   750
qed
hoelzl@51523
   751
hoelzl@51523
   752
lemma less_RealD:
hoelzl@51523
   753
  assumes Y: "cauchy Y"
hoelzl@51523
   754
  shows "x < Real Y \<Longrightarrow> \<exists>n. x < of_rat (Y n)"
hoelzl@51523
   755
by (erule contrapos_pp, simp add: not_less, erule Real_leI [OF Y])
hoelzl@51523
   756
hoelzl@51523
   757
lemma of_nat_less_two_power:
hoelzl@51523
   758
  "of_nat n < (2::'a::linordered_idom) ^ n"
hoelzl@51523
   759
apply (induct n)
hoelzl@51523
   760
apply simp
hoelzl@51523
   761
apply (subgoal_tac "(1::'a) \<le> 2 ^ n")
hoelzl@51523
   762
apply (drule (1) add_le_less_mono, simp)
hoelzl@51523
   763
apply simp
hoelzl@51523
   764
done
hoelzl@51523
   765
hoelzl@51523
   766
lemma complete_real:
hoelzl@51523
   767
  fixes S :: "real set"
hoelzl@51523
   768
  assumes "\<exists>x. x \<in> S" and "\<exists>z. \<forall>x\<in>S. x \<le> z"
hoelzl@51523
   769
  shows "\<exists>y. (\<forall>x\<in>S. x \<le> y) \<and> (\<forall>z. (\<forall>x\<in>S. x \<le> z) \<longrightarrow> y \<le> z)"
hoelzl@51523
   770
proof -
hoelzl@51523
   771
  obtain x where x: "x \<in> S" using assms(1) ..
hoelzl@51523
   772
  obtain z where z: "\<forall>x\<in>S. x \<le> z" using assms(2) ..
hoelzl@51523
   773
hoelzl@51523
   774
  def P \<equiv> "\<lambda>x. \<forall>y\<in>S. y \<le> of_rat x"
hoelzl@51523
   775
  obtain a where a: "\<not> P a"
hoelzl@51523
   776
  proof
hoelzl@51523
   777
    have "of_int (floor (x - 1)) \<le> x - 1" by (rule of_int_floor_le)
hoelzl@51523
   778
    also have "x - 1 < x" by simp
hoelzl@51523
   779
    finally have "of_int (floor (x - 1)) < x" .
hoelzl@51523
   780
    hence "\<not> x \<le> of_int (floor (x - 1))" by (simp only: not_le)
hoelzl@51523
   781
    then show "\<not> P (of_int (floor (x - 1)))"
hoelzl@51523
   782
      unfolding P_def of_rat_of_int_eq using x by fast
hoelzl@51523
   783
  qed
hoelzl@51523
   784
  obtain b where b: "P b"
hoelzl@51523
   785
  proof
hoelzl@51523
   786
    show "P (of_int (ceiling z))"
hoelzl@51523
   787
    unfolding P_def of_rat_of_int_eq
hoelzl@51523
   788
    proof
hoelzl@51523
   789
      fix y assume "y \<in> S"
hoelzl@51523
   790
      hence "y \<le> z" using z by simp
hoelzl@51523
   791
      also have "z \<le> of_int (ceiling z)" by (rule le_of_int_ceiling)
hoelzl@51523
   792
      finally show "y \<le> of_int (ceiling z)" .
hoelzl@51523
   793
    qed
hoelzl@51523
   794
  qed
hoelzl@51523
   795
hoelzl@51523
   796
  def avg \<equiv> "\<lambda>x y :: rat. x/2 + y/2"
hoelzl@51523
   797
  def bisect \<equiv> "\<lambda>(x, y). if P (avg x y) then (x, avg x y) else (avg x y, y)"
hoelzl@51523
   798
  def A \<equiv> "\<lambda>n. fst ((bisect ^^ n) (a, b))"
hoelzl@51523
   799
  def B \<equiv> "\<lambda>n. snd ((bisect ^^ n) (a, b))"
hoelzl@51523
   800
  def C \<equiv> "\<lambda>n. avg (A n) (B n)"
hoelzl@51523
   801
  have A_0 [simp]: "A 0 = a" unfolding A_def by simp
hoelzl@51523
   802
  have B_0 [simp]: "B 0 = b" unfolding B_def by simp
hoelzl@51523
   803
  have A_Suc [simp]: "\<And>n. A (Suc n) = (if P (C n) then A n else C n)"
hoelzl@51523
   804
    unfolding A_def B_def C_def bisect_def split_def by simp
hoelzl@51523
   805
  have B_Suc [simp]: "\<And>n. B (Suc n) = (if P (C n) then C n else B n)"
hoelzl@51523
   806
    unfolding A_def B_def C_def bisect_def split_def by simp
hoelzl@51523
   807
hoelzl@51523
   808
  have width: "\<And>n. B n - A n = (b - a) / 2^n"
hoelzl@51523
   809
    apply (simp add: eq_divide_eq)
hoelzl@51523
   810
    apply (induct_tac n, simp)
hoelzl@51523
   811
    apply (simp add: C_def avg_def algebra_simps)
hoelzl@51523
   812
    done
hoelzl@51523
   813
hoelzl@51523
   814
  have twos: "\<And>y r :: rat. 0 < r \<Longrightarrow> \<exists>n. y / 2 ^ n < r"
hoelzl@51523
   815
    apply (simp add: divide_less_eq)
hoelzl@51523
   816
    apply (subst mult_commute)
hoelzl@51523
   817
    apply (frule_tac y=y in ex_less_of_nat_mult)
hoelzl@51523
   818
    apply clarify
hoelzl@51523
   819
    apply (rule_tac x=n in exI)
hoelzl@51523
   820
    apply (erule less_trans)
hoelzl@51523
   821
    apply (rule mult_strict_right_mono)
hoelzl@51523
   822
    apply (rule le_less_trans [OF _ of_nat_less_two_power])
hoelzl@51523
   823
    apply simp
hoelzl@51523
   824
    apply assumption
hoelzl@51523
   825
    done
hoelzl@51523
   826
hoelzl@51523
   827
  have PA: "\<And>n. \<not> P (A n)"
hoelzl@51523
   828
    by (induct_tac n, simp_all add: a)
hoelzl@51523
   829
  have PB: "\<And>n. P (B n)"
hoelzl@51523
   830
    by (induct_tac n, simp_all add: b)
hoelzl@51523
   831
  have ab: "a < b"
hoelzl@51523
   832
    using a b unfolding P_def
hoelzl@51523
   833
    apply (clarsimp simp add: not_le)
hoelzl@51523
   834
    apply (drule (1) bspec)
hoelzl@51523
   835
    apply (drule (1) less_le_trans)
hoelzl@51523
   836
    apply (simp add: of_rat_less)
hoelzl@51523
   837
    done
hoelzl@51523
   838
  have AB: "\<And>n. A n < B n"
hoelzl@51523
   839
    by (induct_tac n, simp add: ab, simp add: C_def avg_def)
hoelzl@51523
   840
  have A_mono: "\<And>i j. i \<le> j \<Longrightarrow> A i \<le> A j"
hoelzl@51523
   841
    apply (auto simp add: le_less [where 'a=nat])
hoelzl@51523
   842
    apply (erule less_Suc_induct)
hoelzl@51523
   843
    apply (clarsimp simp add: C_def avg_def)
hoelzl@51523
   844
    apply (simp add: add_divide_distrib [symmetric])
hoelzl@51523
   845
    apply (rule AB [THEN less_imp_le])
hoelzl@51523
   846
    apply simp
hoelzl@51523
   847
    done
hoelzl@51523
   848
  have B_mono: "\<And>i j. i \<le> j \<Longrightarrow> B j \<le> B i"
hoelzl@51523
   849
    apply (auto simp add: le_less [where 'a=nat])
hoelzl@51523
   850
    apply (erule less_Suc_induct)
hoelzl@51523
   851
    apply (clarsimp simp add: C_def avg_def)
hoelzl@51523
   852
    apply (simp add: add_divide_distrib [symmetric])
hoelzl@51523
   853
    apply (rule AB [THEN less_imp_le])
hoelzl@51523
   854
    apply simp
hoelzl@51523
   855
    done
hoelzl@51523
   856
  have cauchy_lemma:
hoelzl@51523
   857
    "\<And>X. \<forall>n. \<forall>i\<ge>n. A n \<le> X i \<and> X i \<le> B n \<Longrightarrow> cauchy X"
hoelzl@51523
   858
    apply (rule cauchyI)
hoelzl@51523
   859
    apply (drule twos [where y="b - a"])
hoelzl@51523
   860
    apply (erule exE)
hoelzl@51523
   861
    apply (rule_tac x=n in exI, clarify, rename_tac i j)
hoelzl@51523
   862
    apply (rule_tac y="B n - A n" in le_less_trans) defer
hoelzl@51523
   863
    apply (simp add: width)
hoelzl@51523
   864
    apply (drule_tac x=n in spec)
hoelzl@51523
   865
    apply (frule_tac x=i in spec, drule (1) mp)
hoelzl@51523
   866
    apply (frule_tac x=j in spec, drule (1) mp)
hoelzl@51523
   867
    apply (frule A_mono, drule B_mono)
hoelzl@51523
   868
    apply (frule A_mono, drule B_mono)
hoelzl@51523
   869
    apply arith
hoelzl@51523
   870
    done
hoelzl@51523
   871
  have "cauchy A"
hoelzl@51523
   872
    apply (rule cauchy_lemma [rule_format])
hoelzl@51523
   873
    apply (simp add: A_mono)
hoelzl@51523
   874
    apply (erule order_trans [OF less_imp_le [OF AB] B_mono])
hoelzl@51523
   875
    done
hoelzl@51523
   876
  have "cauchy B"
hoelzl@51523
   877
    apply (rule cauchy_lemma [rule_format])
hoelzl@51523
   878
    apply (simp add: B_mono)
hoelzl@51523
   879
    apply (erule order_trans [OF A_mono less_imp_le [OF AB]])
hoelzl@51523
   880
    done
hoelzl@51523
   881
  have 1: "\<forall>x\<in>S. x \<le> Real B"
hoelzl@51523
   882
  proof
hoelzl@51523
   883
    fix x assume "x \<in> S"
hoelzl@51523
   884
    then show "x \<le> Real B"
hoelzl@51523
   885
      using PB [unfolded P_def] `cauchy B`
hoelzl@51523
   886
      by (simp add: le_RealI)
hoelzl@51523
   887
  qed
hoelzl@51523
   888
  have 2: "\<forall>z. (\<forall>x\<in>S. x \<le> z) \<longrightarrow> Real A \<le> z"
hoelzl@51523
   889
    apply clarify
hoelzl@51523
   890
    apply (erule contrapos_pp)
hoelzl@51523
   891
    apply (simp add: not_le)
hoelzl@51523
   892
    apply (drule less_RealD [OF `cauchy A`], clarify)
hoelzl@51523
   893
    apply (subgoal_tac "\<not> P (A n)")
hoelzl@51523
   894
    apply (simp add: P_def not_le, clarify)
hoelzl@51523
   895
    apply (erule rev_bexI)
hoelzl@51523
   896
    apply (erule (1) less_trans)
hoelzl@51523
   897
    apply (simp add: PA)
hoelzl@51523
   898
    done
hoelzl@51523
   899
  have "vanishes (\<lambda>n. (b - a) / 2 ^ n)"
hoelzl@51523
   900
  proof (rule vanishesI)
hoelzl@51523
   901
    fix r :: rat assume "0 < r"
hoelzl@51523
   902
    then obtain k where k: "\<bar>b - a\<bar> / 2 ^ k < r"
hoelzl@51523
   903
      using twos by fast
hoelzl@51523
   904
    have "\<forall>n\<ge>k. \<bar>(b - a) / 2 ^ n\<bar> < r"
hoelzl@51523
   905
    proof (clarify)
hoelzl@51523
   906
      fix n assume n: "k \<le> n"
hoelzl@51523
   907
      have "\<bar>(b - a) / 2 ^ n\<bar> = \<bar>b - a\<bar> / 2 ^ n"
hoelzl@51523
   908
        by simp
hoelzl@51523
   909
      also have "\<dots> \<le> \<bar>b - a\<bar> / 2 ^ k"
hoelzl@51523
   910
        using n by (simp add: divide_left_mono mult_pos_pos)
hoelzl@51523
   911
      also note k
hoelzl@51523
   912
      finally show "\<bar>(b - a) / 2 ^ n\<bar> < r" .
hoelzl@51523
   913
    qed
hoelzl@51523
   914
    thus "\<exists>k. \<forall>n\<ge>k. \<bar>(b - a) / 2 ^ n\<bar> < r" ..
hoelzl@51523
   915
  qed
hoelzl@51523
   916
  hence 3: "Real B = Real A"
hoelzl@51523
   917
    by (simp add: eq_Real `cauchy A` `cauchy B` width)
hoelzl@51523
   918
  show "\<exists>y. (\<forall>x\<in>S. x \<le> y) \<and> (\<forall>z. (\<forall>x\<in>S. x \<le> z) \<longrightarrow> y \<le> z)"
hoelzl@51523
   919
    using 1 2 3 by (rule_tac x="Real B" in exI, simp)
hoelzl@51523
   920
qed
hoelzl@51523
   921
hoelzl@51775
   922
instantiation real :: linear_continuum
hoelzl@51523
   923
begin
hoelzl@51523
   924
hoelzl@51523
   925
subsection{*Supremum of a set of reals*}
hoelzl@51523
   926
hoelzl@54281
   927
definition "Sup X = (LEAST z::real. \<forall>x\<in>X. x \<le> z)"
hoelzl@54281
   928
definition "Inf (X::real set) = - Sup (uminus ` X)"
hoelzl@51523
   929
hoelzl@51523
   930
instance
hoelzl@51523
   931
proof
hoelzl@54258
   932
  { fix x :: real and X :: "real set"
hoelzl@54258
   933
    assume x: "x \<in> X" "bdd_above X"
hoelzl@51523
   934
    then obtain s where s: "\<forall>y\<in>X. y \<le> s" "\<And>z. \<forall>y\<in>X. y \<le> z \<Longrightarrow> s \<le> z"
hoelzl@54258
   935
      using complete_real[of X] unfolding bdd_above_def by blast
hoelzl@51523
   936
    then show "x \<le> Sup X"
hoelzl@51523
   937
      unfolding Sup_real_def by (rule LeastI2_order) (auto simp: x) }
hoelzl@51523
   938
  note Sup_upper = this
hoelzl@51523
   939
hoelzl@51523
   940
  { fix z :: real and X :: "real set"
hoelzl@51523
   941
    assume x: "X \<noteq> {}" and z: "\<And>x. x \<in> X \<Longrightarrow> x \<le> z"
hoelzl@51523
   942
    then obtain s where s: "\<forall>y\<in>X. y \<le> s" "\<And>z. \<forall>y\<in>X. y \<le> z \<Longrightarrow> s \<le> z"
hoelzl@51523
   943
      using complete_real[of X] by blast
hoelzl@51523
   944
    then have "Sup X = s"
hoelzl@51523
   945
      unfolding Sup_real_def by (best intro: Least_equality)  
wenzelm@53374
   946
    also from s z have "... \<le> z"
hoelzl@51523
   947
      by blast
hoelzl@51523
   948
    finally show "Sup X \<le> z" . }
hoelzl@51523
   949
  note Sup_least = this
hoelzl@51523
   950
hoelzl@54281
   951
  { fix x :: real and X :: "real set" assume x: "x \<in> X" "bdd_below X" then show "Inf X \<le> x"
hoelzl@54281
   952
      using Sup_upper[of "-x" "uminus ` X"] by (auto simp: Inf_real_def) }
hoelzl@54281
   953
  { fix z :: real and X :: "real set" assume "X \<noteq> {}" "\<And>x. x \<in> X \<Longrightarrow> z \<le> x" then show "z \<le> Inf X"
hoelzl@54281
   954
      using Sup_least[of "uminus ` X" "- z"] by (force simp: Inf_real_def) }
hoelzl@51775
   955
  show "\<exists>a b::real. a \<noteq> b"
hoelzl@51775
   956
    using zero_neq_one by blast
hoelzl@51523
   957
qed
hoelzl@51523
   958
end
hoelzl@51523
   959
hoelzl@51523
   960
hoelzl@51523
   961
subsection {* Hiding implementation details *}
hoelzl@51523
   962
hoelzl@51523
   963
hide_const (open) vanishes cauchy positive Real
hoelzl@51523
   964
hoelzl@51523
   965
declare Real_induct [induct del]
hoelzl@51523
   966
declare Abs_real_induct [induct del]
hoelzl@51523
   967
declare Abs_real_cases [cases del]
hoelzl@51523
   968
kuncar@53652
   969
lifting_update real.lifting
kuncar@53652
   970
lifting_forget real.lifting
kuncar@51956
   971
  
hoelzl@51523
   972
subsection{*More Lemmas*}
hoelzl@51523
   973
hoelzl@51523
   974
text {* BH: These lemmas should not be necessary; they should be
hoelzl@51523
   975
covered by existing simp rules and simplification procedures. *}
hoelzl@51523
   976
hoelzl@51523
   977
lemma real_mult_left_cancel: "(c::real) \<noteq> 0 ==> (c*a=c*b) = (a=b)"
hoelzl@51523
   978
by simp (* redundant with mult_cancel_left *)
hoelzl@51523
   979
hoelzl@51523
   980
lemma real_mult_right_cancel: "(c::real) \<noteq> 0 ==> (a*c=b*c) = (a=b)"
hoelzl@51523
   981
by simp (* redundant with mult_cancel_right *)
hoelzl@51523
   982
hoelzl@51523
   983
lemma real_mult_less_iff1 [simp]: "(0::real) < z ==> (x*z < y*z) = (x < y)"
hoelzl@51523
   984
by simp (* solved by linordered_ring_less_cancel_factor simproc *)
hoelzl@51523
   985
hoelzl@51523
   986
lemma real_mult_le_cancel_iff1 [simp]: "(0::real) < z ==> (x*z \<le> y*z) = (x\<le>y)"
hoelzl@51523
   987
by simp (* solved by linordered_ring_le_cancel_factor simproc *)
hoelzl@51523
   988
hoelzl@51523
   989
lemma real_mult_le_cancel_iff2 [simp]: "(0::real) < z ==> (z*x \<le> z*y) = (x\<le>y)"
hoelzl@51523
   990
by simp (* solved by linordered_ring_le_cancel_factor simproc *)
hoelzl@51523
   991
hoelzl@51523
   992
hoelzl@51523
   993
subsection {* Embedding numbers into the Reals *}
hoelzl@51523
   994
hoelzl@51523
   995
abbreviation
hoelzl@51523
   996
  real_of_nat :: "nat \<Rightarrow> real"
hoelzl@51523
   997
where
hoelzl@51523
   998
  "real_of_nat \<equiv> of_nat"
hoelzl@51523
   999
hoelzl@51523
  1000
abbreviation
hoelzl@51523
  1001
  real_of_int :: "int \<Rightarrow> real"
hoelzl@51523
  1002
where
hoelzl@51523
  1003
  "real_of_int \<equiv> of_int"
hoelzl@51523
  1004
hoelzl@51523
  1005
abbreviation
hoelzl@51523
  1006
  real_of_rat :: "rat \<Rightarrow> real"
hoelzl@51523
  1007
where
hoelzl@51523
  1008
  "real_of_rat \<equiv> of_rat"
hoelzl@51523
  1009
hoelzl@51523
  1010
consts
hoelzl@51523
  1011
  (*overloaded constant for injecting other types into "real"*)
hoelzl@51523
  1012
  real :: "'a => real"
hoelzl@51523
  1013
hoelzl@51523
  1014
defs (overloaded)
hoelzl@51523
  1015
  real_of_nat_def [code_unfold]: "real == real_of_nat"
hoelzl@51523
  1016
  real_of_int_def [code_unfold]: "real == real_of_int"
hoelzl@51523
  1017
hoelzl@51523
  1018
declare [[coercion_enabled]]
hoelzl@51523
  1019
declare [[coercion "real::nat\<Rightarrow>real"]]
hoelzl@51523
  1020
declare [[coercion "real::int\<Rightarrow>real"]]
hoelzl@51523
  1021
declare [[coercion "int"]]
hoelzl@51523
  1022
hoelzl@51523
  1023
declare [[coercion_map map]]
hoelzl@51523
  1024
declare [[coercion_map "% f g h x. g (h (f x))"]]
hoelzl@51523
  1025
declare [[coercion_map "% f g (x,y) . (f x, g y)"]]
hoelzl@51523
  1026
hoelzl@51523
  1027
lemma real_eq_of_nat: "real = of_nat"
hoelzl@51523
  1028
  unfolding real_of_nat_def ..
hoelzl@51523
  1029
hoelzl@51523
  1030
lemma real_eq_of_int: "real = of_int"
hoelzl@51523
  1031
  unfolding real_of_int_def ..
hoelzl@51523
  1032
hoelzl@51523
  1033
lemma real_of_int_zero [simp]: "real (0::int) = 0"  
hoelzl@51523
  1034
by (simp add: real_of_int_def) 
hoelzl@51523
  1035
hoelzl@51523
  1036
lemma real_of_one [simp]: "real (1::int) = (1::real)"
hoelzl@51523
  1037
by (simp add: real_of_int_def) 
hoelzl@51523
  1038
hoelzl@51523
  1039
lemma real_of_int_add [simp]: "real(x + y) = real (x::int) + real y"
hoelzl@51523
  1040
by (simp add: real_of_int_def) 
hoelzl@51523
  1041
hoelzl@51523
  1042
lemma real_of_int_minus [simp]: "real(-x) = -real (x::int)"
hoelzl@51523
  1043
by (simp add: real_of_int_def) 
hoelzl@51523
  1044
hoelzl@51523
  1045
lemma real_of_int_diff [simp]: "real(x - y) = real (x::int) - real y"
hoelzl@51523
  1046
by (simp add: real_of_int_def) 
hoelzl@51523
  1047
hoelzl@51523
  1048
lemma real_of_int_mult [simp]: "real(x * y) = real (x::int) * real y"
hoelzl@51523
  1049
by (simp add: real_of_int_def) 
hoelzl@51523
  1050
hoelzl@51523
  1051
lemma real_of_int_power [simp]: "real (x ^ n) = real (x::int) ^ n"
hoelzl@51523
  1052
by (simp add: real_of_int_def of_int_power)
hoelzl@51523
  1053
hoelzl@51523
  1054
lemmas power_real_of_int = real_of_int_power [symmetric]
hoelzl@51523
  1055
hoelzl@51523
  1056
lemma real_of_int_setsum [simp]: "real ((SUM x:A. f x)::int) = (SUM x:A. real(f x))"
hoelzl@51523
  1057
  apply (subst real_eq_of_int)+
hoelzl@51523
  1058
  apply (rule of_int_setsum)
hoelzl@51523
  1059
done
hoelzl@51523
  1060
hoelzl@51523
  1061
lemma real_of_int_setprod [simp]: "real ((PROD x:A. f x)::int) = 
hoelzl@51523
  1062
    (PROD x:A. real(f x))"
hoelzl@51523
  1063
  apply (subst real_eq_of_int)+
hoelzl@51523
  1064
  apply (rule of_int_setprod)
hoelzl@51523
  1065
done
hoelzl@51523
  1066
hoelzl@51523
  1067
lemma real_of_int_zero_cancel [simp, algebra, presburger]: "(real x = 0) = (x = (0::int))"
hoelzl@51523
  1068
by (simp add: real_of_int_def) 
hoelzl@51523
  1069
hoelzl@51523
  1070
lemma real_of_int_inject [iff, algebra, presburger]: "(real (x::int) = real y) = (x = y)"
hoelzl@51523
  1071
by (simp add: real_of_int_def) 
hoelzl@51523
  1072
hoelzl@51523
  1073
lemma real_of_int_less_iff [iff, presburger]: "(real (x::int) < real y) = (x < y)"
hoelzl@51523
  1074
by (simp add: real_of_int_def) 
hoelzl@51523
  1075
hoelzl@51523
  1076
lemma real_of_int_le_iff [simp, presburger]: "(real (x::int) \<le> real y) = (x \<le> y)"
hoelzl@51523
  1077
by (simp add: real_of_int_def) 
hoelzl@51523
  1078
hoelzl@51523
  1079
lemma real_of_int_gt_zero_cancel_iff [simp, presburger]: "(0 < real (n::int)) = (0 < n)"
hoelzl@51523
  1080
by (simp add: real_of_int_def) 
hoelzl@51523
  1081
hoelzl@51523
  1082
lemma real_of_int_ge_zero_cancel_iff [simp, presburger]: "(0 <= real (n::int)) = (0 <= n)"
hoelzl@51523
  1083
by (simp add: real_of_int_def) 
hoelzl@51523
  1084
hoelzl@51523
  1085
lemma real_of_int_lt_zero_cancel_iff [simp, presburger]: "(real (n::int) < 0) = (n < 0)" 
hoelzl@51523
  1086
by (simp add: real_of_int_def)
hoelzl@51523
  1087
hoelzl@51523
  1088
lemma real_of_int_le_zero_cancel_iff [simp, presburger]: "(real (n::int) <= 0) = (n <= 0)"
hoelzl@51523
  1089
by (simp add: real_of_int_def)
hoelzl@51523
  1090
hoelzl@51523
  1091
lemma one_less_real_of_int_cancel_iff: "1 < real (i :: int) \<longleftrightarrow> 1 < i"
hoelzl@51523
  1092
  unfolding real_of_one[symmetric] real_of_int_less_iff ..
hoelzl@51523
  1093
hoelzl@51523
  1094
lemma one_le_real_of_int_cancel_iff: "1 \<le> real (i :: int) \<longleftrightarrow> 1 \<le> i"
hoelzl@51523
  1095
  unfolding real_of_one[symmetric] real_of_int_le_iff ..
hoelzl@51523
  1096
hoelzl@51523
  1097
lemma real_of_int_less_one_cancel_iff: "real (i :: int) < 1 \<longleftrightarrow> i < 1"
hoelzl@51523
  1098
  unfolding real_of_one[symmetric] real_of_int_less_iff ..
hoelzl@51523
  1099
hoelzl@51523
  1100
lemma real_of_int_le_one_cancel_iff: "real (i :: int) \<le> 1 \<longleftrightarrow> i \<le> 1"
hoelzl@51523
  1101
  unfolding real_of_one[symmetric] real_of_int_le_iff ..
hoelzl@51523
  1102
hoelzl@51523
  1103
lemma real_of_int_abs [simp]: "real (abs x) = abs(real (x::int))"
hoelzl@51523
  1104
by (auto simp add: abs_if)
hoelzl@51523
  1105
hoelzl@51523
  1106
lemma int_less_real_le: "((n::int) < m) = (real n + 1 <= real m)"
hoelzl@51523
  1107
  apply (subgoal_tac "real n + 1 = real (n + 1)")
hoelzl@51523
  1108
  apply (simp del: real_of_int_add)
hoelzl@51523
  1109
  apply auto
hoelzl@51523
  1110
done
hoelzl@51523
  1111
hoelzl@51523
  1112
lemma int_le_real_less: "((n::int) <= m) = (real n < real m + 1)"
hoelzl@51523
  1113
  apply (subgoal_tac "real m + 1 = real (m + 1)")
hoelzl@51523
  1114
  apply (simp del: real_of_int_add)
hoelzl@51523
  1115
  apply simp
hoelzl@51523
  1116
done
hoelzl@51523
  1117
hoelzl@51523
  1118
lemma real_of_int_div_aux: "(real (x::int)) / (real d) = 
hoelzl@51523
  1119
    real (x div d) + (real (x mod d)) / (real d)"
hoelzl@51523
  1120
proof -
hoelzl@51523
  1121
  have "x = (x div d) * d + x mod d"
hoelzl@51523
  1122
    by auto
hoelzl@51523
  1123
  then have "real x = real (x div d) * real d + real(x mod d)"
hoelzl@51523
  1124
    by (simp only: real_of_int_mult [THEN sym] real_of_int_add [THEN sym])
hoelzl@51523
  1125
  then have "real x / real d = ... / real d"
hoelzl@51523
  1126
    by simp
hoelzl@51523
  1127
  then show ?thesis
hoelzl@51523
  1128
    by (auto simp add: add_divide_distrib algebra_simps)
hoelzl@51523
  1129
qed
hoelzl@51523
  1130
hoelzl@51523
  1131
lemma real_of_int_div: "(d :: int) dvd n ==>
hoelzl@51523
  1132
    real(n div d) = real n / real d"
hoelzl@51523
  1133
  apply (subst real_of_int_div_aux)
hoelzl@51523
  1134
  apply simp
hoelzl@51523
  1135
  apply (simp add: dvd_eq_mod_eq_0)
hoelzl@51523
  1136
done
hoelzl@51523
  1137
hoelzl@51523
  1138
lemma real_of_int_div2:
hoelzl@51523
  1139
  "0 <= real (n::int) / real (x) - real (n div x)"
hoelzl@51523
  1140
  apply (case_tac "x = 0")
hoelzl@51523
  1141
  apply simp
hoelzl@51523
  1142
  apply (case_tac "0 < x")
hoelzl@51523
  1143
  apply (simp add: algebra_simps)
hoelzl@51523
  1144
  apply (subst real_of_int_div_aux)
hoelzl@51523
  1145
  apply simp
hoelzl@51523
  1146
  apply (subst zero_le_divide_iff)
hoelzl@51523
  1147
  apply auto
hoelzl@51523
  1148
  apply (simp add: algebra_simps)
hoelzl@51523
  1149
  apply (subst real_of_int_div_aux)
hoelzl@51523
  1150
  apply simp
hoelzl@51523
  1151
  apply (subst zero_le_divide_iff)
hoelzl@51523
  1152
  apply auto
hoelzl@51523
  1153
done
hoelzl@51523
  1154
hoelzl@51523
  1155
lemma real_of_int_div3:
hoelzl@51523
  1156
  "real (n::int) / real (x) - real (n div x) <= 1"
hoelzl@51523
  1157
  apply (simp add: algebra_simps)
hoelzl@51523
  1158
  apply (subst real_of_int_div_aux)
hoelzl@51523
  1159
  apply (auto simp add: divide_le_eq intro: order_less_imp_le)
hoelzl@51523
  1160
done
hoelzl@51523
  1161
hoelzl@51523
  1162
lemma real_of_int_div4: "real (n div x) <= real (n::int) / real x" 
hoelzl@51523
  1163
by (insert real_of_int_div2 [of n x], simp)
hoelzl@51523
  1164
hoelzl@51523
  1165
lemma Ints_real_of_int [simp]: "real (x::int) \<in> Ints"
hoelzl@51523
  1166
unfolding real_of_int_def by (rule Ints_of_int)
hoelzl@51523
  1167
hoelzl@51523
  1168
hoelzl@51523
  1169
subsection{*Embedding the Naturals into the Reals*}
hoelzl@51523
  1170
hoelzl@51523
  1171
lemma real_of_nat_zero [simp]: "real (0::nat) = 0"
hoelzl@51523
  1172
by (simp add: real_of_nat_def)
hoelzl@51523
  1173
hoelzl@51523
  1174
lemma real_of_nat_1 [simp]: "real (1::nat) = 1"
hoelzl@51523
  1175
by (simp add: real_of_nat_def)
hoelzl@51523
  1176
hoelzl@51523
  1177
lemma real_of_nat_one [simp]: "real (Suc 0) = (1::real)"
hoelzl@51523
  1178
by (simp add: real_of_nat_def)
hoelzl@51523
  1179
hoelzl@51523
  1180
lemma real_of_nat_add [simp]: "real (m + n) = real (m::nat) + real n"
hoelzl@51523
  1181
by (simp add: real_of_nat_def)
hoelzl@51523
  1182
hoelzl@51523
  1183
(*Not for addsimps: often the LHS is used to represent a positive natural*)
hoelzl@51523
  1184
lemma real_of_nat_Suc: "real (Suc n) = real n + (1::real)"
hoelzl@51523
  1185
by (simp add: real_of_nat_def)
hoelzl@51523
  1186
hoelzl@51523
  1187
lemma real_of_nat_less_iff [iff]: 
hoelzl@51523
  1188
     "(real (n::nat) < real m) = (n < m)"
hoelzl@51523
  1189
by (simp add: real_of_nat_def)
hoelzl@51523
  1190
hoelzl@51523
  1191
lemma real_of_nat_le_iff [iff]: "(real (n::nat) \<le> real m) = (n \<le> m)"
hoelzl@51523
  1192
by (simp add: real_of_nat_def)
hoelzl@51523
  1193
hoelzl@51523
  1194
lemma real_of_nat_ge_zero [iff]: "0 \<le> real (n::nat)"
hoelzl@51523
  1195
by (simp add: real_of_nat_def)
hoelzl@51523
  1196
hoelzl@51523
  1197
lemma real_of_nat_Suc_gt_zero: "0 < real (Suc n)"
hoelzl@51523
  1198
by (simp add: real_of_nat_def del: of_nat_Suc)
hoelzl@51523
  1199
hoelzl@51523
  1200
lemma real_of_nat_mult [simp]: "real (m * n) = real (m::nat) * real n"
hoelzl@51523
  1201
by (simp add: real_of_nat_def of_nat_mult)
hoelzl@51523
  1202
hoelzl@51523
  1203
lemma real_of_nat_power [simp]: "real (m ^ n) = real (m::nat) ^ n"
hoelzl@51523
  1204
by (simp add: real_of_nat_def of_nat_power)
hoelzl@51523
  1205
hoelzl@51523
  1206
lemmas power_real_of_nat = real_of_nat_power [symmetric]
hoelzl@51523
  1207
hoelzl@51523
  1208
lemma real_of_nat_setsum [simp]: "real ((SUM x:A. f x)::nat) = 
hoelzl@51523
  1209
    (SUM x:A. real(f x))"
hoelzl@51523
  1210
  apply (subst real_eq_of_nat)+
hoelzl@51523
  1211
  apply (rule of_nat_setsum)
hoelzl@51523
  1212
done
hoelzl@51523
  1213
hoelzl@51523
  1214
lemma real_of_nat_setprod [simp]: "real ((PROD x:A. f x)::nat) = 
hoelzl@51523
  1215
    (PROD x:A. real(f x))"
hoelzl@51523
  1216
  apply (subst real_eq_of_nat)+
hoelzl@51523
  1217
  apply (rule of_nat_setprod)
hoelzl@51523
  1218
done
hoelzl@51523
  1219
hoelzl@51523
  1220
lemma real_of_card: "real (card A) = setsum (%x.1) A"
hoelzl@51523
  1221
  apply (subst card_eq_setsum)
hoelzl@51523
  1222
  apply (subst real_of_nat_setsum)
hoelzl@51523
  1223
  apply simp
hoelzl@51523
  1224
done
hoelzl@51523
  1225
hoelzl@51523
  1226
lemma real_of_nat_inject [iff]: "(real (n::nat) = real m) = (n = m)"
hoelzl@51523
  1227
by (simp add: real_of_nat_def)
hoelzl@51523
  1228
hoelzl@51523
  1229
lemma real_of_nat_zero_iff [iff]: "(real (n::nat) = 0) = (n = 0)"
hoelzl@51523
  1230
by (simp add: real_of_nat_def)
hoelzl@51523
  1231
hoelzl@51523
  1232
lemma real_of_nat_diff: "n \<le> m ==> real (m - n) = real (m::nat) - real n"
hoelzl@51523
  1233
by (simp add: add: real_of_nat_def of_nat_diff)
hoelzl@51523
  1234
hoelzl@51523
  1235
lemma real_of_nat_gt_zero_cancel_iff [simp]: "(0 < real (n::nat)) = (0 < n)"
hoelzl@51523
  1236
by (auto simp: real_of_nat_def)
hoelzl@51523
  1237
hoelzl@51523
  1238
lemma real_of_nat_le_zero_cancel_iff [simp]: "(real (n::nat) \<le> 0) = (n = 0)"
hoelzl@51523
  1239
by (simp add: add: real_of_nat_def)
hoelzl@51523
  1240
hoelzl@51523
  1241
lemma not_real_of_nat_less_zero [simp]: "~ real (n::nat) < 0"
hoelzl@51523
  1242
by (simp add: add: real_of_nat_def)
hoelzl@51523
  1243
hoelzl@51523
  1244
lemma nat_less_real_le: "((n::nat) < m) = (real n + 1 <= real m)"
hoelzl@51523
  1245
  apply (subgoal_tac "real n + 1 = real (Suc n)")
hoelzl@51523
  1246
  apply simp
hoelzl@51523
  1247
  apply (auto simp add: real_of_nat_Suc)
hoelzl@51523
  1248
done
hoelzl@51523
  1249
hoelzl@51523
  1250
lemma nat_le_real_less: "((n::nat) <= m) = (real n < real m + 1)"
hoelzl@51523
  1251
  apply (subgoal_tac "real m + 1 = real (Suc m)")
hoelzl@51523
  1252
  apply (simp add: less_Suc_eq_le)
hoelzl@51523
  1253
  apply (simp add: real_of_nat_Suc)
hoelzl@51523
  1254
done
hoelzl@51523
  1255
hoelzl@51523
  1256
lemma real_of_nat_div_aux: "(real (x::nat)) / (real d) = 
hoelzl@51523
  1257
    real (x div d) + (real (x mod d)) / (real d)"
hoelzl@51523
  1258
proof -
hoelzl@51523
  1259
  have "x = (x div d) * d + x mod d"
hoelzl@51523
  1260
    by auto
hoelzl@51523
  1261
  then have "real x = real (x div d) * real d + real(x mod d)"
hoelzl@51523
  1262
    by (simp only: real_of_nat_mult [THEN sym] real_of_nat_add [THEN sym])
hoelzl@51523
  1263
  then have "real x / real d = \<dots> / real d"
hoelzl@51523
  1264
    by simp
hoelzl@51523
  1265
  then show ?thesis
hoelzl@51523
  1266
    by (auto simp add: add_divide_distrib algebra_simps)
hoelzl@51523
  1267
qed
hoelzl@51523
  1268
hoelzl@51523
  1269
lemma real_of_nat_div: "(d :: nat) dvd n ==>
hoelzl@51523
  1270
    real(n div d) = real n / real d"
hoelzl@51523
  1271
  by (subst real_of_nat_div_aux)
hoelzl@51523
  1272
    (auto simp add: dvd_eq_mod_eq_0 [symmetric])
hoelzl@51523
  1273
hoelzl@51523
  1274
lemma real_of_nat_div2:
hoelzl@51523
  1275
  "0 <= real (n::nat) / real (x) - real (n div x)"
hoelzl@51523
  1276
apply (simp add: algebra_simps)
hoelzl@51523
  1277
apply (subst real_of_nat_div_aux)
hoelzl@51523
  1278
apply simp
hoelzl@51523
  1279
apply (subst zero_le_divide_iff)
hoelzl@51523
  1280
apply simp
hoelzl@51523
  1281
done
hoelzl@51523
  1282
hoelzl@51523
  1283
lemma real_of_nat_div3:
hoelzl@51523
  1284
  "real (n::nat) / real (x) - real (n div x) <= 1"
hoelzl@51523
  1285
apply(case_tac "x = 0")
hoelzl@51523
  1286
apply (simp)
hoelzl@51523
  1287
apply (simp add: algebra_simps)
hoelzl@51523
  1288
apply (subst real_of_nat_div_aux)
hoelzl@51523
  1289
apply simp
hoelzl@51523
  1290
done
hoelzl@51523
  1291
hoelzl@51523
  1292
lemma real_of_nat_div4: "real (n div x) <= real (n::nat) / real x" 
hoelzl@51523
  1293
by (insert real_of_nat_div2 [of n x], simp)
hoelzl@51523
  1294
hoelzl@51523
  1295
lemma real_of_int_of_nat_eq [simp]: "real (of_nat n :: int) = real n"
hoelzl@51523
  1296
by (simp add: real_of_int_def real_of_nat_def)
hoelzl@51523
  1297
hoelzl@51523
  1298
lemma real_nat_eq_real [simp]: "0 <= x ==> real(nat x) = real x"
hoelzl@51523
  1299
  apply (subgoal_tac "real(int(nat x)) = real(nat x)")
hoelzl@51523
  1300
  apply force
hoelzl@51523
  1301
  apply (simp only: real_of_int_of_nat_eq)
hoelzl@51523
  1302
done
hoelzl@51523
  1303
hoelzl@51523
  1304
lemma Nats_real_of_nat [simp]: "real (n::nat) \<in> Nats"
hoelzl@51523
  1305
unfolding real_of_nat_def by (rule of_nat_in_Nats)
hoelzl@51523
  1306
hoelzl@51523
  1307
lemma Ints_real_of_nat [simp]: "real (n::nat) \<in> Ints"
hoelzl@51523
  1308
unfolding real_of_nat_def by (rule Ints_of_nat)
hoelzl@51523
  1309
hoelzl@51523
  1310
subsection {* The Archimedean Property of the Reals *}
hoelzl@51523
  1311
hoelzl@51523
  1312
theorem reals_Archimedean:
hoelzl@51523
  1313
  assumes x_pos: "0 < x"
hoelzl@51523
  1314
  shows "\<exists>n. inverse (real (Suc n)) < x"
hoelzl@51523
  1315
  unfolding real_of_nat_def using x_pos
hoelzl@51523
  1316
  by (rule ex_inverse_of_nat_Suc_less)
hoelzl@51523
  1317
hoelzl@51523
  1318
lemma reals_Archimedean2: "\<exists>n. (x::real) < real (n::nat)"
hoelzl@51523
  1319
  unfolding real_of_nat_def by (rule ex_less_of_nat)
hoelzl@51523
  1320
hoelzl@51523
  1321
lemma reals_Archimedean3:
hoelzl@51523
  1322
  assumes x_greater_zero: "0 < x"
hoelzl@51523
  1323
  shows "\<forall>(y::real). \<exists>(n::nat). y < real n * x"
hoelzl@51523
  1324
  unfolding real_of_nat_def using `0 < x`
hoelzl@51523
  1325
  by (auto intro: ex_less_of_nat_mult)
hoelzl@51523
  1326
hoelzl@51523
  1327
hoelzl@51523
  1328
subsection{* Rationals *}
hoelzl@51523
  1329
hoelzl@51523
  1330
lemma Rats_real_nat[simp]: "real(n::nat) \<in> \<rat>"
hoelzl@51523
  1331
by (simp add: real_eq_of_nat)
hoelzl@51523
  1332
hoelzl@51523
  1333
hoelzl@51523
  1334
lemma Rats_eq_int_div_int:
hoelzl@51523
  1335
  "\<rat> = { real(i::int)/real(j::int) |i j. j \<noteq> 0}" (is "_ = ?S")
hoelzl@51523
  1336
proof
hoelzl@51523
  1337
  show "\<rat> \<subseteq> ?S"
hoelzl@51523
  1338
  proof
hoelzl@51523
  1339
    fix x::real assume "x : \<rat>"
hoelzl@51523
  1340
    then obtain r where "x = of_rat r" unfolding Rats_def ..
hoelzl@51523
  1341
    have "of_rat r : ?S"
hoelzl@51523
  1342
      by (cases r)(auto simp add:of_rat_rat real_eq_of_int)
hoelzl@51523
  1343
    thus "x : ?S" using `x = of_rat r` by simp
hoelzl@51523
  1344
  qed
hoelzl@51523
  1345
next
hoelzl@51523
  1346
  show "?S \<subseteq> \<rat>"
hoelzl@51523
  1347
  proof(auto simp:Rats_def)
hoelzl@51523
  1348
    fix i j :: int assume "j \<noteq> 0"
hoelzl@51523
  1349
    hence "real i / real j = of_rat(Fract i j)"
hoelzl@51523
  1350
      by (simp add:of_rat_rat real_eq_of_int)
hoelzl@51523
  1351
    thus "real i / real j \<in> range of_rat" by blast
hoelzl@51523
  1352
  qed
hoelzl@51523
  1353
qed
hoelzl@51523
  1354
hoelzl@51523
  1355
lemma Rats_eq_int_div_nat:
hoelzl@51523
  1356
  "\<rat> = { real(i::int)/real(n::nat) |i n. n \<noteq> 0}"
hoelzl@51523
  1357
proof(auto simp:Rats_eq_int_div_int)
hoelzl@51523
  1358
  fix i j::int assume "j \<noteq> 0"
hoelzl@51523
  1359
  show "EX (i'::int) (n::nat). real i/real j = real i'/real n \<and> 0<n"
hoelzl@51523
  1360
  proof cases
hoelzl@51523
  1361
    assume "j>0"
hoelzl@51523
  1362
    hence "real i/real j = real i/real(nat j) \<and> 0<nat j"
hoelzl@51523
  1363
      by (simp add: real_eq_of_int real_eq_of_nat of_nat_nat)
hoelzl@51523
  1364
    thus ?thesis by blast
hoelzl@51523
  1365
  next
hoelzl@51523
  1366
    assume "~ j>0"
hoelzl@51523
  1367
    hence "real i/real j = real(-i)/real(nat(-j)) \<and> 0<nat(-j)" using `j\<noteq>0`
hoelzl@51523
  1368
      by (simp add: real_eq_of_int real_eq_of_nat of_nat_nat)
hoelzl@51523
  1369
    thus ?thesis by blast
hoelzl@51523
  1370
  qed
hoelzl@51523
  1371
next
hoelzl@51523
  1372
  fix i::int and n::nat assume "0 < n"
hoelzl@51523
  1373
  hence "real i/real n = real i/real(int n) \<and> int n \<noteq> 0" by simp
hoelzl@51523
  1374
  thus "\<exists>(i'::int) j::int. real i/real n = real i'/real j \<and> j \<noteq> 0" by blast
hoelzl@51523
  1375
qed
hoelzl@51523
  1376
hoelzl@51523
  1377
lemma Rats_abs_nat_div_natE:
hoelzl@51523
  1378
  assumes "x \<in> \<rat>"
hoelzl@51523
  1379
  obtains m n :: nat
hoelzl@51523
  1380
  where "n \<noteq> 0" and "\<bar>x\<bar> = real m / real n" and "gcd m n = 1"
hoelzl@51523
  1381
proof -
hoelzl@51523
  1382
  from `x \<in> \<rat>` obtain i::int and n::nat where "n \<noteq> 0" and "x = real i / real n"
hoelzl@51523
  1383
    by(auto simp add: Rats_eq_int_div_nat)
hoelzl@51523
  1384
  hence "\<bar>x\<bar> = real(nat(abs i)) / real n" by simp
hoelzl@51523
  1385
  then obtain m :: nat where x_rat: "\<bar>x\<bar> = real m / real n" by blast
hoelzl@51523
  1386
  let ?gcd = "gcd m n"
hoelzl@51523
  1387
  from `n\<noteq>0` have gcd: "?gcd \<noteq> 0" by simp
hoelzl@51523
  1388
  let ?k = "m div ?gcd"
hoelzl@51523
  1389
  let ?l = "n div ?gcd"
hoelzl@51523
  1390
  let ?gcd' = "gcd ?k ?l"
hoelzl@51523
  1391
  have "?gcd dvd m" .. then have gcd_k: "?gcd * ?k = m"
hoelzl@51523
  1392
    by (rule dvd_mult_div_cancel)
hoelzl@51523
  1393
  have "?gcd dvd n" .. then have gcd_l: "?gcd * ?l = n"
hoelzl@51523
  1394
    by (rule dvd_mult_div_cancel)
hoelzl@51523
  1395
  from `n\<noteq>0` and gcd_l have "?l \<noteq> 0" by (auto iff del: neq0_conv)
hoelzl@51523
  1396
  moreover
hoelzl@51523
  1397
  have "\<bar>x\<bar> = real ?k / real ?l"
hoelzl@51523
  1398
  proof -
hoelzl@51523
  1399
    from gcd have "real ?k / real ?l =
hoelzl@51523
  1400
        real (?gcd * ?k) / real (?gcd * ?l)" by simp
hoelzl@51523
  1401
    also from gcd_k and gcd_l have "\<dots> = real m / real n" by simp
hoelzl@51523
  1402
    also from x_rat have "\<dots> = \<bar>x\<bar>" ..
hoelzl@51523
  1403
    finally show ?thesis ..
hoelzl@51523
  1404
  qed
hoelzl@51523
  1405
  moreover
hoelzl@51523
  1406
  have "?gcd' = 1"
hoelzl@51523
  1407
  proof -
hoelzl@51523
  1408
    have "?gcd * ?gcd' = gcd (?gcd * ?k) (?gcd * ?l)"
hoelzl@51523
  1409
      by (rule gcd_mult_distrib_nat)
hoelzl@51523
  1410
    with gcd_k gcd_l have "?gcd * ?gcd' = ?gcd" by simp
hoelzl@51523
  1411
    with gcd show ?thesis by auto
hoelzl@51523
  1412
  qed
hoelzl@51523
  1413
  ultimately show ?thesis ..
hoelzl@51523
  1414
qed
hoelzl@51523
  1415
hoelzl@51523
  1416
subsection{*Density of the Rational Reals in the Reals*}
hoelzl@51523
  1417
hoelzl@51523
  1418
text{* This density proof is due to Stefan Richter and was ported by TN.  The
hoelzl@51523
  1419
original source is \emph{Real Analysis} by H.L. Royden.
hoelzl@51523
  1420
It employs the Archimedean property of the reals. *}
hoelzl@51523
  1421
hoelzl@51523
  1422
lemma Rats_dense_in_real:
hoelzl@51523
  1423
  fixes x :: real
hoelzl@51523
  1424
  assumes "x < y" shows "\<exists>r\<in>\<rat>. x < r \<and> r < y"
hoelzl@51523
  1425
proof -
hoelzl@51523
  1426
  from `x<y` have "0 < y-x" by simp
hoelzl@51523
  1427
  with reals_Archimedean obtain q::nat 
hoelzl@51523
  1428
    where q: "inverse (real q) < y-x" and "0 < q" by auto
hoelzl@51523
  1429
  def p \<equiv> "ceiling (y * real q) - 1"
hoelzl@51523
  1430
  def r \<equiv> "of_int p / real q"
hoelzl@51523
  1431
  from q have "x < y - inverse (real q)" by simp
hoelzl@51523
  1432
  also have "y - inverse (real q) \<le> r"
hoelzl@51523
  1433
    unfolding r_def p_def
hoelzl@51523
  1434
    by (simp add: le_divide_eq left_diff_distrib le_of_int_ceiling `0 < q`)
hoelzl@51523
  1435
  finally have "x < r" .
hoelzl@51523
  1436
  moreover have "r < y"
hoelzl@51523
  1437
    unfolding r_def p_def
hoelzl@51523
  1438
    by (simp add: divide_less_eq diff_less_eq `0 < q`
hoelzl@51523
  1439
      less_ceiling_iff [symmetric])
hoelzl@51523
  1440
  moreover from r_def have "r \<in> \<rat>" by simp
hoelzl@51523
  1441
  ultimately show ?thesis by fast
hoelzl@51523
  1442
qed
hoelzl@51523
  1443
hoelzl@51523
  1444
hoelzl@51523
  1445
hoelzl@51523
  1446
subsection{*Numerals and Arithmetic*}
hoelzl@51523
  1447
hoelzl@51523
  1448
lemma [code_abbrev]:
hoelzl@51523
  1449
  "real_of_int (numeral k) = numeral k"
haftmann@54489
  1450
  "real_of_int (- numeral k) = - numeral k"
hoelzl@51523
  1451
  by simp_all
hoelzl@51523
  1452
haftmann@54489
  1453
text{*Collapse applications of @{const real} to @{const numeral}*}
hoelzl@51523
  1454
lemma real_numeral [simp]:
hoelzl@51523
  1455
  "real (numeral v :: int) = numeral v"
haftmann@54489
  1456
  "real (- numeral v :: int) = - numeral v"
hoelzl@51523
  1457
by (simp_all add: real_of_int_def)
hoelzl@51523
  1458
hoelzl@51523
  1459
lemma real_of_nat_numeral [simp]:
hoelzl@51523
  1460
  "real (numeral v :: nat) = numeral v"
hoelzl@51523
  1461
by (simp add: real_of_nat_def)
hoelzl@51523
  1462
hoelzl@51523
  1463
declaration {*
hoelzl@51523
  1464
  K (Lin_Arith.add_inj_thms [@{thm real_of_nat_le_iff} RS iffD2, @{thm real_of_nat_inject} RS iffD2]
hoelzl@51523
  1465
    (* not needed because x < (y::nat) can be rewritten as Suc x <= y: real_of_nat_less_iff RS iffD2 *)
hoelzl@51523
  1466
  #> Lin_Arith.add_inj_thms [@{thm real_of_int_le_iff} RS iffD2, @{thm real_of_int_inject} RS iffD2]
hoelzl@51523
  1467
    (* not needed because x < (y::int) can be rewritten as x + 1 <= y: real_of_int_less_iff RS iffD2 *)
hoelzl@51523
  1468
  #> Lin_Arith.add_simps [@{thm real_of_nat_zero}, @{thm real_of_nat_Suc}, @{thm real_of_nat_add},
hoelzl@51523
  1469
      @{thm real_of_nat_mult}, @{thm real_of_int_zero}, @{thm real_of_one},
hoelzl@51523
  1470
      @{thm real_of_int_add}, @{thm real_of_int_minus}, @{thm real_of_int_diff},
hoelzl@51523
  1471
      @{thm real_of_int_mult}, @{thm real_of_int_of_nat_eq},
hoelzl@51523
  1472
      @{thm real_of_nat_numeral}, @{thm real_numeral(1)}, @{thm real_numeral(2)}]
hoelzl@51523
  1473
  #> Lin_Arith.add_inj_const (@{const_name real}, @{typ "nat \<Rightarrow> real"})
hoelzl@51523
  1474
  #> Lin_Arith.add_inj_const (@{const_name real}, @{typ "int \<Rightarrow> real"}))
hoelzl@51523
  1475
*}
hoelzl@51523
  1476
hoelzl@51523
  1477
hoelzl@51523
  1478
subsection{* Simprules combining x+y and 0: ARE THEY NEEDED?*}
hoelzl@51523
  1479
hoelzl@51523
  1480
lemma real_add_minus_iff [simp]: "(x + - a = (0::real)) = (x=a)" 
hoelzl@51523
  1481
by arith
hoelzl@51523
  1482
hoelzl@51523
  1483
text {* FIXME: redundant with @{text add_eq_0_iff} below *}
hoelzl@51523
  1484
lemma real_add_eq_0_iff: "(x+y = (0::real)) = (y = -x)"
hoelzl@51523
  1485
by auto
hoelzl@51523
  1486
hoelzl@51523
  1487
lemma real_add_less_0_iff: "(x+y < (0::real)) = (y < -x)"
hoelzl@51523
  1488
by auto
hoelzl@51523
  1489
hoelzl@51523
  1490
lemma real_0_less_add_iff: "((0::real) < x+y) = (-x < y)"
hoelzl@51523
  1491
by auto
hoelzl@51523
  1492
hoelzl@51523
  1493
lemma real_add_le_0_iff: "(x+y \<le> (0::real)) = (y \<le> -x)"
hoelzl@51523
  1494
by auto
hoelzl@51523
  1495
hoelzl@51523
  1496
lemma real_0_le_add_iff: "((0::real) \<le> x+y) = (-x \<le> y)"
hoelzl@51523
  1497
by auto
hoelzl@51523
  1498
hoelzl@51523
  1499
subsection {* Lemmas about powers *}
hoelzl@51523
  1500
hoelzl@51523
  1501
text {* FIXME: declare this in Rings.thy or not at all *}
hoelzl@51523
  1502
declare abs_mult_self [simp]
hoelzl@51523
  1503
hoelzl@51523
  1504
(* used by Import/HOL/real.imp *)
hoelzl@51523
  1505
lemma two_realpow_ge_one: "(1::real) \<le> 2 ^ n"
hoelzl@51523
  1506
by simp
hoelzl@51523
  1507
hoelzl@51523
  1508
lemma two_realpow_gt [simp]: "real (n::nat) < 2 ^ n"
hoelzl@51523
  1509
apply (induct "n")
hoelzl@51523
  1510
apply (auto simp add: real_of_nat_Suc)
hoelzl@51523
  1511
apply (subst mult_2)
hoelzl@51523
  1512
apply (erule add_less_le_mono)
hoelzl@51523
  1513
apply (rule two_realpow_ge_one)
hoelzl@51523
  1514
done
hoelzl@51523
  1515
hoelzl@51523
  1516
text {* TODO: no longer real-specific; rename and move elsewhere *}
hoelzl@51523
  1517
lemma realpow_Suc_le_self:
hoelzl@51523
  1518
  fixes r :: "'a::linordered_semidom"
hoelzl@51523
  1519
  shows "[| 0 \<le> r; r \<le> 1 |] ==> r ^ Suc n \<le> r"
hoelzl@51523
  1520
by (insert power_decreasing [of 1 "Suc n" r], simp)
hoelzl@51523
  1521
hoelzl@51523
  1522
text {* TODO: no longer real-specific; rename and move elsewhere *}
hoelzl@51523
  1523
lemma realpow_minus_mult:
hoelzl@51523
  1524
  fixes x :: "'a::monoid_mult"
hoelzl@51523
  1525
  shows "0 < n \<Longrightarrow> x ^ (n - 1) * x = x ^ n"
hoelzl@51523
  1526
by (simp add: power_commutes split add: nat_diff_split)
hoelzl@51523
  1527
hoelzl@51523
  1528
text {* FIXME: declare this [simp] for all types, or not at all *}
hoelzl@51523
  1529
lemma real_two_squares_add_zero_iff [simp]:
hoelzl@51523
  1530
  "(x * x + y * y = 0) = ((x::real) = 0 \<and> y = 0)"
hoelzl@51523
  1531
by (rule sum_squares_eq_zero_iff)
hoelzl@51523
  1532
hoelzl@51523
  1533
text {* FIXME: declare this [simp] for all types, or not at all *}
hoelzl@51523
  1534
lemma realpow_two_sum_zero_iff [simp]:
wenzelm@53076
  1535
     "(x\<^sup>2 + y\<^sup>2 = (0::real)) = (x = 0 & y = 0)"
hoelzl@51523
  1536
by (rule sum_power2_eq_zero_iff)
hoelzl@51523
  1537
hoelzl@51523
  1538
lemma real_minus_mult_self_le [simp]: "-(u * u) \<le> (x * (x::real))"
hoelzl@51523
  1539
by (rule_tac y = 0 in order_trans, auto)
hoelzl@51523
  1540
wenzelm@53076
  1541
lemma realpow_square_minus_le [simp]: "- u\<^sup>2 \<le> (x::real)\<^sup>2"
hoelzl@51523
  1542
by (auto simp add: power2_eq_square)
hoelzl@51523
  1543
hoelzl@51523
  1544
hoelzl@51523
  1545
lemma numeral_power_le_real_of_nat_cancel_iff[simp]:
hoelzl@51523
  1546
  "(numeral x::real) ^ n \<le> real a \<longleftrightarrow> (numeral x::nat) ^ n \<le> a"
hoelzl@51523
  1547
  unfolding real_of_nat_le_iff[symmetric] by simp
hoelzl@51523
  1548
hoelzl@51523
  1549
lemma real_of_nat_le_numeral_power_cancel_iff[simp]:
hoelzl@51523
  1550
  "real a \<le> (numeral x::real) ^ n \<longleftrightarrow> a \<le> (numeral x::nat) ^ n"
hoelzl@51523
  1551
  unfolding real_of_nat_le_iff[symmetric] by simp
hoelzl@51523
  1552
hoelzl@51523
  1553
lemma numeral_power_le_real_of_int_cancel_iff[simp]:
hoelzl@51523
  1554
  "(numeral x::real) ^ n \<le> real a \<longleftrightarrow> (numeral x::int) ^ n \<le> a"
hoelzl@51523
  1555
  unfolding real_of_int_le_iff[symmetric] by simp
hoelzl@51523
  1556
hoelzl@51523
  1557
lemma real_of_int_le_numeral_power_cancel_iff[simp]:
hoelzl@51523
  1558
  "real a \<le> (numeral x::real) ^ n \<longleftrightarrow> a \<le> (numeral x::int) ^ n"
hoelzl@51523
  1559
  unfolding real_of_int_le_iff[symmetric] by simp
hoelzl@51523
  1560
hoelzl@51523
  1561
lemma neg_numeral_power_le_real_of_int_cancel_iff[simp]:
haftmann@54489
  1562
  "(- numeral x::real) ^ n \<le> real a \<longleftrightarrow> (- numeral x::int) ^ n \<le> a"
hoelzl@51523
  1563
  unfolding real_of_int_le_iff[symmetric] by simp
hoelzl@51523
  1564
hoelzl@51523
  1565
lemma real_of_int_le_neg_numeral_power_cancel_iff[simp]:
haftmann@54489
  1566
  "real a \<le> (- numeral x::real) ^ n \<longleftrightarrow> a \<le> (- numeral x::int) ^ n"
hoelzl@51523
  1567
  unfolding real_of_int_le_iff[symmetric] by simp
hoelzl@51523
  1568
hoelzl@51523
  1569
subsection{*Density of the Reals*}
hoelzl@51523
  1570
hoelzl@51523
  1571
lemma real_lbound_gt_zero:
hoelzl@51523
  1572
     "[| (0::real) < d1; 0 < d2 |] ==> \<exists>e. 0 < e & e < d1 & e < d2"
hoelzl@51523
  1573
apply (rule_tac x = " (min d1 d2) /2" in exI)
hoelzl@51523
  1574
apply (simp add: min_def)
hoelzl@51523
  1575
done
hoelzl@51523
  1576
hoelzl@51523
  1577
hoelzl@51523
  1578
text{*Similar results are proved in @{text Fields}*}
hoelzl@51523
  1579
lemma real_less_half_sum: "x < y ==> x < (x+y) / (2::real)"
hoelzl@51523
  1580
  by auto
hoelzl@51523
  1581
hoelzl@51523
  1582
lemma real_gt_half_sum: "x < y ==> (x+y)/(2::real) < y"
hoelzl@51523
  1583
  by auto
hoelzl@51523
  1584
hoelzl@51523
  1585
lemma real_sum_of_halves: "x/2 + x/2 = (x::real)"
hoelzl@51523
  1586
  by simp
hoelzl@51523
  1587
hoelzl@51523
  1588
subsection{*Absolute Value Function for the Reals*}
hoelzl@51523
  1589
hoelzl@51523
  1590
lemma abs_minus_add_cancel: "abs(x + (-y)) = abs (y + (-(x::real)))"
hoelzl@51523
  1591
by (simp add: abs_if)
hoelzl@51523
  1592
hoelzl@51523
  1593
(* FIXME: redundant, but used by Integration/RealRandVar.thy in AFP *)
hoelzl@51523
  1594
lemma abs_le_interval_iff: "(abs x \<le> r) = (-r\<le>x & x\<le>(r::real))"
hoelzl@51523
  1595
by (force simp add: abs_le_iff)
hoelzl@51523
  1596
hoelzl@51523
  1597
lemma abs_add_one_gt_zero: "(0::real) < 1 + abs(x)"
hoelzl@51523
  1598
by (simp add: abs_if)
hoelzl@51523
  1599
hoelzl@51523
  1600
lemma abs_real_of_nat_cancel [simp]: "abs (real x) = real (x::nat)"
hoelzl@51523
  1601
by (rule abs_of_nonneg [OF real_of_nat_ge_zero])
hoelzl@51523
  1602
hoelzl@51523
  1603
lemma abs_add_one_not_less_self: "~ abs(x) + (1::real) < x"
hoelzl@51523
  1604
by simp
hoelzl@51523
  1605
 
hoelzl@51523
  1606
lemma abs_sum_triangle_ineq: "abs ((x::real) + y + (-l + -m)) \<le> abs(x + -l) + abs(y + -m)"
hoelzl@51523
  1607
by simp
hoelzl@51523
  1608
hoelzl@51523
  1609
hoelzl@51523
  1610
subsection{*Floor and Ceiling Functions from the Reals to the Integers*}
hoelzl@51523
  1611
hoelzl@51523
  1612
(* FIXME: theorems for negative numerals *)
hoelzl@51523
  1613
lemma numeral_less_real_of_int_iff [simp]:
hoelzl@51523
  1614
     "((numeral n) < real (m::int)) = (numeral n < m)"
hoelzl@51523
  1615
apply auto
hoelzl@51523
  1616
apply (rule real_of_int_less_iff [THEN iffD1])
hoelzl@51523
  1617
apply (drule_tac [2] real_of_int_less_iff [THEN iffD2], auto)
hoelzl@51523
  1618
done
hoelzl@51523
  1619
hoelzl@51523
  1620
lemma numeral_less_real_of_int_iff2 [simp]:
hoelzl@51523
  1621
     "(real (m::int) < (numeral n)) = (m < numeral n)"
hoelzl@51523
  1622
apply auto
hoelzl@51523
  1623
apply (rule real_of_int_less_iff [THEN iffD1])
hoelzl@51523
  1624
apply (drule_tac [2] real_of_int_less_iff [THEN iffD2], auto)
hoelzl@51523
  1625
done
hoelzl@51523
  1626
hoelzl@51523
  1627
lemma numeral_le_real_of_int_iff [simp]:
hoelzl@51523
  1628
     "((numeral n) \<le> real (m::int)) = (numeral n \<le> m)"
hoelzl@51523
  1629
by (simp add: linorder_not_less [symmetric])
hoelzl@51523
  1630
hoelzl@51523
  1631
lemma numeral_le_real_of_int_iff2 [simp]:
hoelzl@51523
  1632
     "(real (m::int) \<le> (numeral n)) = (m \<le> numeral n)"
hoelzl@51523
  1633
by (simp add: linorder_not_less [symmetric])
hoelzl@51523
  1634
hoelzl@51523
  1635
lemma floor_real_of_nat [simp]: "floor (real (n::nat)) = int n"
hoelzl@51523
  1636
unfolding real_of_nat_def by simp
hoelzl@51523
  1637
hoelzl@51523
  1638
lemma floor_minus_real_of_nat [simp]: "floor (- real (n::nat)) = - int n"
hoelzl@51523
  1639
unfolding real_of_nat_def by (simp add: floor_minus)
hoelzl@51523
  1640
hoelzl@51523
  1641
lemma floor_real_of_int [simp]: "floor (real (n::int)) = n"
hoelzl@51523
  1642
unfolding real_of_int_def by simp
hoelzl@51523
  1643
hoelzl@51523
  1644
lemma floor_minus_real_of_int [simp]: "floor (- real (n::int)) = - n"
hoelzl@51523
  1645
unfolding real_of_int_def by (simp add: floor_minus)
hoelzl@51523
  1646
hoelzl@51523
  1647
lemma real_lb_ub_int: " \<exists>n::int. real n \<le> r & r < real (n+1)"
hoelzl@51523
  1648
unfolding real_of_int_def by (rule floor_exists)
hoelzl@51523
  1649
hoelzl@51523
  1650
lemma lemma_floor:
hoelzl@51523
  1651
  assumes a1: "real m \<le> r" and a2: "r < real n + 1"
hoelzl@51523
  1652
  shows "m \<le> (n::int)"
hoelzl@51523
  1653
proof -
hoelzl@51523
  1654
  have "real m < real n + 1" using a1 a2 by (rule order_le_less_trans)
hoelzl@51523
  1655
  also have "... = real (n + 1)" by simp
hoelzl@51523
  1656
  finally have "m < n + 1" by (simp only: real_of_int_less_iff)
hoelzl@51523
  1657
  thus ?thesis by arith
hoelzl@51523
  1658
qed
hoelzl@51523
  1659
hoelzl@51523
  1660
lemma real_of_int_floor_le [simp]: "real (floor r) \<le> r"
hoelzl@51523
  1661
unfolding real_of_int_def by (rule of_int_floor_le)
hoelzl@51523
  1662
hoelzl@51523
  1663
lemma lemma_floor2: "real n < real (x::int) + 1 ==> n \<le> x"
hoelzl@51523
  1664
by (auto intro: lemma_floor)
hoelzl@51523
  1665
hoelzl@51523
  1666
lemma real_of_int_floor_cancel [simp]:
hoelzl@51523
  1667
    "(real (floor x) = x) = (\<exists>n::int. x = real n)"
hoelzl@51523
  1668
  using floor_real_of_int by metis
hoelzl@51523
  1669
hoelzl@51523
  1670
lemma floor_eq: "[| real n < x; x < real n + 1 |] ==> floor x = n"
hoelzl@51523
  1671
  unfolding real_of_int_def using floor_unique [of n x] by simp
hoelzl@51523
  1672
hoelzl@51523
  1673
lemma floor_eq2: "[| real n \<le> x; x < real n + 1 |] ==> floor x = n"
hoelzl@51523
  1674
  unfolding real_of_int_def by (rule floor_unique)
hoelzl@51523
  1675
hoelzl@51523
  1676
lemma floor_eq3: "[| real n < x; x < real (Suc n) |] ==> nat(floor x) = n"
hoelzl@51523
  1677
apply (rule inj_int [THEN injD])
hoelzl@51523
  1678
apply (simp add: real_of_nat_Suc)
hoelzl@51523
  1679
apply (simp add: real_of_nat_Suc floor_eq floor_eq [where n = "int n"])
hoelzl@51523
  1680
done
hoelzl@51523
  1681
hoelzl@51523
  1682
lemma floor_eq4: "[| real n \<le> x; x < real (Suc n) |] ==> nat(floor x) = n"
hoelzl@51523
  1683
apply (drule order_le_imp_less_or_eq)
hoelzl@51523
  1684
apply (auto intro: floor_eq3)
hoelzl@51523
  1685
done
hoelzl@51523
  1686
hoelzl@51523
  1687
lemma real_of_int_floor_ge_diff_one [simp]: "r - 1 \<le> real(floor r)"
hoelzl@51523
  1688
  unfolding real_of_int_def using floor_correct [of r] by simp
hoelzl@51523
  1689
hoelzl@51523
  1690
lemma real_of_int_floor_gt_diff_one [simp]: "r - 1 < real(floor r)"
hoelzl@51523
  1691
  unfolding real_of_int_def using floor_correct [of r] by simp
hoelzl@51523
  1692
hoelzl@51523
  1693
lemma real_of_int_floor_add_one_ge [simp]: "r \<le> real(floor r) + 1"
hoelzl@51523
  1694
  unfolding real_of_int_def using floor_correct [of r] by simp
hoelzl@51523
  1695
hoelzl@51523
  1696
lemma real_of_int_floor_add_one_gt [simp]: "r < real(floor r) + 1"
hoelzl@51523
  1697
  unfolding real_of_int_def using floor_correct [of r] by simp
hoelzl@51523
  1698
hoelzl@51523
  1699
lemma le_floor: "real a <= x ==> a <= floor x"
hoelzl@51523
  1700
  unfolding real_of_int_def by (simp add: le_floor_iff)
hoelzl@51523
  1701
hoelzl@51523
  1702
lemma real_le_floor: "a <= floor x ==> real a <= x"
hoelzl@51523
  1703
  unfolding real_of_int_def by (simp add: le_floor_iff)
hoelzl@51523
  1704
hoelzl@51523
  1705
lemma le_floor_eq: "(a <= floor x) = (real a <= x)"
hoelzl@51523
  1706
  unfolding real_of_int_def by (rule le_floor_iff)
hoelzl@51523
  1707
hoelzl@51523
  1708
lemma floor_less_eq: "(floor x < a) = (x < real a)"
hoelzl@51523
  1709
  unfolding real_of_int_def by (rule floor_less_iff)
hoelzl@51523
  1710
hoelzl@51523
  1711
lemma less_floor_eq: "(a < floor x) = (real a + 1 <= x)"
hoelzl@51523
  1712
  unfolding real_of_int_def by (rule less_floor_iff)
hoelzl@51523
  1713
hoelzl@51523
  1714
lemma floor_le_eq: "(floor x <= a) = (x < real a + 1)"
hoelzl@51523
  1715
  unfolding real_of_int_def by (rule floor_le_iff)
hoelzl@51523
  1716
hoelzl@51523
  1717
lemma floor_add [simp]: "floor (x + real a) = floor x + a"
hoelzl@51523
  1718
  unfolding real_of_int_def by (rule floor_add_of_int)
hoelzl@51523
  1719
hoelzl@51523
  1720
lemma floor_subtract [simp]: "floor (x - real a) = floor x - a"
hoelzl@51523
  1721
  unfolding real_of_int_def by (rule floor_diff_of_int)
hoelzl@51523
  1722
hoelzl@51523
  1723
lemma le_mult_floor:
hoelzl@51523
  1724
  assumes "0 \<le> (a :: real)" and "0 \<le> b"
hoelzl@51523
  1725
  shows "floor a * floor b \<le> floor (a * b)"
hoelzl@51523
  1726
proof -
hoelzl@51523
  1727
  have "real (floor a) \<le> a"
hoelzl@51523
  1728
    and "real (floor b) \<le> b" by auto
hoelzl@51523
  1729
  hence "real (floor a * floor b) \<le> a * b"
hoelzl@51523
  1730
    using assms by (auto intro!: mult_mono)
hoelzl@51523
  1731
  also have "a * b < real (floor (a * b) + 1)" by auto
hoelzl@51523
  1732
  finally show ?thesis unfolding real_of_int_less_iff by simp
hoelzl@51523
  1733
qed
hoelzl@51523
  1734
hoelzl@51523
  1735
lemma floor_divide_eq_div:
hoelzl@51523
  1736
  "floor (real a / real b) = a div b"
hoelzl@51523
  1737
proof cases
hoelzl@51523
  1738
  assume "b \<noteq> 0 \<or> b dvd a"
hoelzl@51523
  1739
  with real_of_int_div3[of a b] show ?thesis
hoelzl@51523
  1740
    by (auto simp: real_of_int_div[symmetric] intro!: floor_eq2 real_of_int_div4 neq_le_trans)
hoelzl@51523
  1741
       (metis add_left_cancel zero_neq_one real_of_int_div_aux real_of_int_inject
hoelzl@51523
  1742
              real_of_int_zero_cancel right_inverse_eq div_self mod_div_trivial)
hoelzl@51523
  1743
qed (auto simp: real_of_int_div)
hoelzl@51523
  1744
hoelzl@51523
  1745
lemma ceiling_real_of_nat [simp]: "ceiling (real (n::nat)) = int n"
hoelzl@51523
  1746
  unfolding real_of_nat_def by simp
hoelzl@51523
  1747
hoelzl@51523
  1748
lemma real_of_int_ceiling_ge [simp]: "r \<le> real (ceiling r)"
hoelzl@51523
  1749
  unfolding real_of_int_def by (rule le_of_int_ceiling)
hoelzl@51523
  1750
hoelzl@51523
  1751
lemma ceiling_real_of_int [simp]: "ceiling (real (n::int)) = n"
hoelzl@51523
  1752
  unfolding real_of_int_def by simp
hoelzl@51523
  1753
hoelzl@51523
  1754
lemma real_of_int_ceiling_cancel [simp]:
hoelzl@51523
  1755
     "(real (ceiling x) = x) = (\<exists>n::int. x = real n)"
hoelzl@51523
  1756
  using ceiling_real_of_int by metis
hoelzl@51523
  1757
hoelzl@51523
  1758
lemma ceiling_eq: "[| real n < x; x < real n + 1 |] ==> ceiling x = n + 1"
hoelzl@51523
  1759
  unfolding real_of_int_def using ceiling_unique [of "n + 1" x] by simp
hoelzl@51523
  1760
hoelzl@51523
  1761
lemma ceiling_eq2: "[| real n < x; x \<le> real n + 1 |] ==> ceiling x = n + 1"
hoelzl@51523
  1762
  unfolding real_of_int_def using ceiling_unique [of "n + 1" x] by simp
hoelzl@51523
  1763
hoelzl@51523
  1764
lemma ceiling_eq3: "[| real n - 1 < x; x \<le> real n  |] ==> ceiling x = n"
hoelzl@51523
  1765
  unfolding real_of_int_def using ceiling_unique [of n x] by simp
hoelzl@51523
  1766
hoelzl@51523
  1767
lemma real_of_int_ceiling_diff_one_le [simp]: "real (ceiling r) - 1 \<le> r"
hoelzl@51523
  1768
  unfolding real_of_int_def using ceiling_correct [of r] by simp
hoelzl@51523
  1769
hoelzl@51523
  1770
lemma real_of_int_ceiling_le_add_one [simp]: "real (ceiling r) \<le> r + 1"
hoelzl@51523
  1771
  unfolding real_of_int_def using ceiling_correct [of r] by simp
hoelzl@51523
  1772
hoelzl@51523
  1773
lemma ceiling_le: "x <= real a ==> ceiling x <= a"
hoelzl@51523
  1774
  unfolding real_of_int_def by (simp add: ceiling_le_iff)
hoelzl@51523
  1775
hoelzl@51523
  1776
lemma ceiling_le_real: "ceiling x <= a ==> x <= real a"
hoelzl@51523
  1777
  unfolding real_of_int_def by (simp add: ceiling_le_iff)
hoelzl@51523
  1778
hoelzl@51523
  1779
lemma ceiling_le_eq: "(ceiling x <= a) = (x <= real a)"
hoelzl@51523
  1780
  unfolding real_of_int_def by (rule ceiling_le_iff)
hoelzl@51523
  1781
hoelzl@51523
  1782
lemma less_ceiling_eq: "(a < ceiling x) = (real a < x)"
hoelzl@51523
  1783
  unfolding real_of_int_def by (rule less_ceiling_iff)
hoelzl@51523
  1784
hoelzl@51523
  1785
lemma ceiling_less_eq: "(ceiling x < a) = (x <= real a - 1)"
hoelzl@51523
  1786
  unfolding real_of_int_def by (rule ceiling_less_iff)
hoelzl@51523
  1787
hoelzl@51523
  1788
lemma le_ceiling_eq: "(a <= ceiling x) = (real a - 1 < x)"
hoelzl@51523
  1789
  unfolding real_of_int_def by (rule le_ceiling_iff)
hoelzl@51523
  1790
hoelzl@51523
  1791
lemma ceiling_add [simp]: "ceiling (x + real a) = ceiling x + a"
hoelzl@51523
  1792
  unfolding real_of_int_def by (rule ceiling_add_of_int)
hoelzl@51523
  1793
hoelzl@51523
  1794
lemma ceiling_subtract [simp]: "ceiling (x - real a) = ceiling x - a"
hoelzl@51523
  1795
  unfolding real_of_int_def by (rule ceiling_diff_of_int)
hoelzl@51523
  1796
hoelzl@51523
  1797
hoelzl@51523
  1798
subsubsection {* Versions for the natural numbers *}
hoelzl@51523
  1799
hoelzl@51523
  1800
definition
hoelzl@51523
  1801
  natfloor :: "real => nat" where
hoelzl@51523
  1802
  "natfloor x = nat(floor x)"
hoelzl@51523
  1803
hoelzl@51523
  1804
definition
hoelzl@51523
  1805
  natceiling :: "real => nat" where
hoelzl@51523
  1806
  "natceiling x = nat(ceiling x)"
hoelzl@51523
  1807
hoelzl@51523
  1808
lemma natfloor_zero [simp]: "natfloor 0 = 0"
hoelzl@51523
  1809
  by (unfold natfloor_def, simp)
hoelzl@51523
  1810
hoelzl@51523
  1811
lemma natfloor_one [simp]: "natfloor 1 = 1"
hoelzl@51523
  1812
  by (unfold natfloor_def, simp)
hoelzl@51523
  1813
hoelzl@51523
  1814
lemma zero_le_natfloor [simp]: "0 <= natfloor x"
hoelzl@51523
  1815
  by (unfold natfloor_def, simp)
hoelzl@51523
  1816
hoelzl@51523
  1817
lemma natfloor_numeral_eq [simp]: "natfloor (numeral n) = numeral n"
hoelzl@51523
  1818
  by (unfold natfloor_def, simp)
hoelzl@51523
  1819
hoelzl@51523
  1820
lemma natfloor_real_of_nat [simp]: "natfloor(real n) = n"
hoelzl@51523
  1821
  by (unfold natfloor_def, simp)
hoelzl@51523
  1822
hoelzl@51523
  1823
lemma real_natfloor_le: "0 <= x ==> real(natfloor x) <= x"
hoelzl@51523
  1824
  by (unfold natfloor_def, simp)
hoelzl@51523
  1825
hoelzl@51523
  1826
lemma natfloor_neg: "x <= 0 ==> natfloor x = 0"
hoelzl@51523
  1827
  unfolding natfloor_def by simp
hoelzl@51523
  1828
hoelzl@51523
  1829
lemma natfloor_mono: "x <= y ==> natfloor x <= natfloor y"
hoelzl@51523
  1830
  unfolding natfloor_def by (intro nat_mono floor_mono)
hoelzl@51523
  1831
hoelzl@51523
  1832
lemma le_natfloor: "real x <= a ==> x <= natfloor a"
hoelzl@51523
  1833
  apply (unfold natfloor_def)
hoelzl@51523
  1834
  apply (subst nat_int [THEN sym])
hoelzl@51523
  1835
  apply (rule nat_mono)
hoelzl@51523
  1836
  apply (rule le_floor)
hoelzl@51523
  1837
  apply simp
hoelzl@51523
  1838
done
hoelzl@51523
  1839
hoelzl@51523
  1840
lemma natfloor_less_iff: "0 \<le> x \<Longrightarrow> natfloor x < n \<longleftrightarrow> x < real n"
hoelzl@51523
  1841
  unfolding natfloor_def real_of_nat_def
hoelzl@51523
  1842
  by (simp add: nat_less_iff floor_less_iff)
hoelzl@51523
  1843
hoelzl@51523
  1844
lemma less_natfloor:
hoelzl@51523
  1845
  assumes "0 \<le> x" and "x < real (n :: nat)"
hoelzl@51523
  1846
  shows "natfloor x < n"
hoelzl@51523
  1847
  using assms by (simp add: natfloor_less_iff)
hoelzl@51523
  1848
hoelzl@51523
  1849
lemma le_natfloor_eq: "0 <= x ==> (a <= natfloor x) = (real a <= x)"
hoelzl@51523
  1850
  apply (rule iffI)
hoelzl@51523
  1851
  apply (rule order_trans)
hoelzl@51523
  1852
  prefer 2
hoelzl@51523
  1853
  apply (erule real_natfloor_le)
hoelzl@51523
  1854
  apply (subst real_of_nat_le_iff)
hoelzl@51523
  1855
  apply assumption
hoelzl@51523
  1856
  apply (erule le_natfloor)
hoelzl@51523
  1857
done
hoelzl@51523
  1858
hoelzl@51523
  1859
lemma le_natfloor_eq_numeral [simp]:
hoelzl@51523
  1860
    "~ neg((numeral n)::int) ==> 0 <= x ==>
hoelzl@51523
  1861
      (numeral n <= natfloor x) = (numeral n <= x)"
hoelzl@51523
  1862
  apply (subst le_natfloor_eq, assumption)
hoelzl@51523
  1863
  apply simp
hoelzl@51523
  1864
done
hoelzl@51523
  1865
hoelzl@51523
  1866
lemma le_natfloor_eq_one [simp]: "(1 <= natfloor x) = (1 <= x)"
hoelzl@51523
  1867
  apply (case_tac "0 <= x")
hoelzl@51523
  1868
  apply (subst le_natfloor_eq, assumption, simp)
hoelzl@51523
  1869
  apply (rule iffI)
hoelzl@51523
  1870
  apply (subgoal_tac "natfloor x <= natfloor 0")
hoelzl@51523
  1871
  apply simp
hoelzl@51523
  1872
  apply (rule natfloor_mono)
hoelzl@51523
  1873
  apply simp
hoelzl@51523
  1874
  apply simp
hoelzl@51523
  1875
done
hoelzl@51523
  1876
hoelzl@51523
  1877
lemma natfloor_eq: "real n <= x ==> x < real n + 1 ==> natfloor x = n"
hoelzl@51523
  1878
  unfolding natfloor_def by (simp add: floor_eq2 [where n="int n"])
hoelzl@51523
  1879
hoelzl@51523
  1880
lemma real_natfloor_add_one_gt: "x < real(natfloor x) + 1"
hoelzl@51523
  1881
  apply (case_tac "0 <= x")
hoelzl@51523
  1882
  apply (unfold natfloor_def)
hoelzl@51523
  1883
  apply simp
hoelzl@51523
  1884
  apply simp_all
hoelzl@51523
  1885
done
hoelzl@51523
  1886
hoelzl@51523
  1887
lemma real_natfloor_gt_diff_one: "x - 1 < real(natfloor x)"
hoelzl@51523
  1888
using real_natfloor_add_one_gt by (simp add: algebra_simps)
hoelzl@51523
  1889
hoelzl@51523
  1890
lemma ge_natfloor_plus_one_imp_gt: "natfloor z + 1 <= n ==> z < real n"
hoelzl@51523
  1891
  apply (subgoal_tac "z < real(natfloor z) + 1")
hoelzl@51523
  1892
  apply arith
hoelzl@51523
  1893
  apply (rule real_natfloor_add_one_gt)
hoelzl@51523
  1894
done
hoelzl@51523
  1895
hoelzl@51523
  1896
lemma natfloor_add [simp]: "0 <= x ==> natfloor (x + real a) = natfloor x + a"
hoelzl@51523
  1897
  unfolding natfloor_def
hoelzl@51523
  1898
  unfolding real_of_int_of_nat_eq [symmetric] floor_add
hoelzl@51523
  1899
  by (simp add: nat_add_distrib)
hoelzl@51523
  1900
hoelzl@51523
  1901
lemma natfloor_add_numeral [simp]:
hoelzl@51523
  1902
    "~neg ((numeral n)::int) ==> 0 <= x ==>
hoelzl@51523
  1903
      natfloor (x + numeral n) = natfloor x + numeral n"
hoelzl@51523
  1904
  by (simp add: natfloor_add [symmetric])
hoelzl@51523
  1905
hoelzl@51523
  1906
lemma natfloor_add_one: "0 <= x ==> natfloor(x + 1) = natfloor x + 1"
hoelzl@51523
  1907
  by (simp add: natfloor_add [symmetric] del: One_nat_def)
hoelzl@51523
  1908
hoelzl@51523
  1909
lemma natfloor_subtract [simp]:
hoelzl@51523
  1910
    "natfloor(x - real a) = natfloor x - a"
hoelzl@51523
  1911
  unfolding natfloor_def real_of_int_of_nat_eq [symmetric] floor_subtract
hoelzl@51523
  1912
  by simp
hoelzl@51523
  1913
hoelzl@51523
  1914
lemma natfloor_div_nat:
hoelzl@51523
  1915
  assumes "1 <= x" and "y > 0"
hoelzl@51523
  1916
  shows "natfloor (x / real y) = natfloor x div y"
hoelzl@51523
  1917
proof (rule natfloor_eq)
hoelzl@51523
  1918
  have "(natfloor x) div y * y \<le> natfloor x"
hoelzl@51523
  1919
    by (rule add_leD1 [where k="natfloor x mod y"], simp)
hoelzl@51523
  1920
  thus "real (natfloor x div y) \<le> x / real y"
hoelzl@51523
  1921
    using assms by (simp add: le_divide_eq le_natfloor_eq)
hoelzl@51523
  1922
  have "natfloor x < (natfloor x) div y * y + y"
hoelzl@51523
  1923
    apply (subst mod_div_equality [symmetric])
hoelzl@51523
  1924
    apply (rule add_strict_left_mono)
hoelzl@51523
  1925
    apply (rule mod_less_divisor)
hoelzl@51523
  1926
    apply fact
hoelzl@51523
  1927
    done
hoelzl@51523
  1928
  thus "x / real y < real (natfloor x div y) + 1"
hoelzl@51523
  1929
    using assms
hoelzl@51523
  1930
    by (simp add: divide_less_eq natfloor_less_iff distrib_right)
hoelzl@51523
  1931
qed
hoelzl@51523
  1932
hoelzl@51523
  1933
lemma le_mult_natfloor:
hoelzl@51523
  1934
  shows "natfloor a * natfloor b \<le> natfloor (a * b)"
hoelzl@51523
  1935
  by (cases "0 <= a & 0 <= b")
hoelzl@51523
  1936
    (auto simp add: le_natfloor_eq mult_nonneg_nonneg mult_mono' real_natfloor_le natfloor_neg)
hoelzl@51523
  1937
hoelzl@51523
  1938
lemma natceiling_zero [simp]: "natceiling 0 = 0"
hoelzl@51523
  1939
  by (unfold natceiling_def, simp)
hoelzl@51523
  1940
hoelzl@51523
  1941
lemma natceiling_one [simp]: "natceiling 1 = 1"
hoelzl@51523
  1942
  by (unfold natceiling_def, simp)
hoelzl@51523
  1943
hoelzl@51523
  1944
lemma zero_le_natceiling [simp]: "0 <= natceiling x"
hoelzl@51523
  1945
  by (unfold natceiling_def, simp)
hoelzl@51523
  1946
hoelzl@51523
  1947
lemma natceiling_numeral_eq [simp]: "natceiling (numeral n) = numeral n"
hoelzl@51523
  1948
  by (unfold natceiling_def, simp)
hoelzl@51523
  1949
hoelzl@51523
  1950
lemma natceiling_real_of_nat [simp]: "natceiling(real n) = n"
hoelzl@51523
  1951
  by (unfold natceiling_def, simp)
hoelzl@51523
  1952
hoelzl@51523
  1953
lemma real_natceiling_ge: "x <= real(natceiling x)"
hoelzl@51523
  1954
  unfolding natceiling_def by (cases "x < 0", simp_all)
hoelzl@51523
  1955
hoelzl@51523
  1956
lemma natceiling_neg: "x <= 0 ==> natceiling x = 0"
hoelzl@51523
  1957
  unfolding natceiling_def by simp
hoelzl@51523
  1958
hoelzl@51523
  1959
lemma natceiling_mono: "x <= y ==> natceiling x <= natceiling y"
hoelzl@51523
  1960
  unfolding natceiling_def by (intro nat_mono ceiling_mono)
hoelzl@51523
  1961
hoelzl@51523
  1962
lemma natceiling_le: "x <= real a ==> natceiling x <= a"
hoelzl@51523
  1963
  unfolding natceiling_def real_of_nat_def
hoelzl@51523
  1964
  by (simp add: nat_le_iff ceiling_le_iff)
hoelzl@51523
  1965
hoelzl@51523
  1966
lemma natceiling_le_eq: "(natceiling x <= a) = (x <= real a)"
hoelzl@51523
  1967
  unfolding natceiling_def real_of_nat_def
hoelzl@51523
  1968
  by (simp add: nat_le_iff ceiling_le_iff)
hoelzl@51523
  1969
hoelzl@51523
  1970
lemma natceiling_le_eq_numeral [simp]:
hoelzl@51523
  1971
    "~ neg((numeral n)::int) ==>
hoelzl@51523
  1972
      (natceiling x <= numeral n) = (x <= numeral n)"
hoelzl@51523
  1973
  by (simp add: natceiling_le_eq)
hoelzl@51523
  1974
hoelzl@51523
  1975
lemma natceiling_le_eq_one: "(natceiling x <= 1) = (x <= 1)"
hoelzl@51523
  1976
  unfolding natceiling_def
hoelzl@51523
  1977
  by (simp add: nat_le_iff ceiling_le_iff)
hoelzl@51523
  1978
hoelzl@51523
  1979
lemma natceiling_eq: "real n < x ==> x <= real n + 1 ==> natceiling x = n + 1"
hoelzl@51523
  1980
  unfolding natceiling_def
hoelzl@51523
  1981
  by (simp add: ceiling_eq2 [where n="int n"])
hoelzl@51523
  1982
hoelzl@51523
  1983
lemma natceiling_add [simp]: "0 <= x ==>
hoelzl@51523
  1984
    natceiling (x + real a) = natceiling x + a"
hoelzl@51523
  1985
  unfolding natceiling_def
hoelzl@51523
  1986
  unfolding real_of_int_of_nat_eq [symmetric] ceiling_add
hoelzl@51523
  1987
  by (simp add: nat_add_distrib)
hoelzl@51523
  1988
hoelzl@51523
  1989
lemma natceiling_add_numeral [simp]:
hoelzl@51523
  1990
    "~ neg ((numeral n)::int) ==> 0 <= x ==>
hoelzl@51523
  1991
      natceiling (x + numeral n) = natceiling x + numeral n"
hoelzl@51523
  1992
  by (simp add: natceiling_add [symmetric])
hoelzl@51523
  1993
hoelzl@51523
  1994
lemma natceiling_add_one: "0 <= x ==> natceiling(x + 1) = natceiling x + 1"
hoelzl@51523
  1995
  by (simp add: natceiling_add [symmetric] del: One_nat_def)
hoelzl@51523
  1996
hoelzl@51523
  1997
lemma natceiling_subtract [simp]: "natceiling(x - real a) = natceiling x - a"
hoelzl@51523
  1998
  unfolding natceiling_def real_of_int_of_nat_eq [symmetric] ceiling_subtract
hoelzl@51523
  1999
  by simp
hoelzl@51523
  2000
hoelzl@51523
  2001
subsection {* Exponentiation with floor *}
hoelzl@51523
  2002
hoelzl@51523
  2003
lemma floor_power:
hoelzl@51523
  2004
  assumes "x = real (floor x)"
hoelzl@51523
  2005
  shows "floor (x ^ n) = floor x ^ n"
hoelzl@51523
  2006
proof -
hoelzl@51523
  2007
  have *: "x ^ n = real (floor x ^ n)"
hoelzl@51523
  2008
    using assms by (induct n arbitrary: x) simp_all
hoelzl@51523
  2009
  show ?thesis unfolding real_of_int_inject[symmetric]
hoelzl@51523
  2010
    unfolding * floor_real_of_int ..
hoelzl@51523
  2011
qed
hoelzl@51523
  2012
hoelzl@51523
  2013
lemma natfloor_power:
hoelzl@51523
  2014
  assumes "x = real (natfloor x)"
hoelzl@51523
  2015
  shows "natfloor (x ^ n) = natfloor x ^ n"
hoelzl@51523
  2016
proof -
hoelzl@51523
  2017
  from assms have "0 \<le> floor x" by auto
hoelzl@51523
  2018
  note assms[unfolded natfloor_def real_nat_eq_real[OF `0 \<le> floor x`]]
hoelzl@51523
  2019
  from floor_power[OF this]
hoelzl@51523
  2020
  show ?thesis unfolding natfloor_def nat_power_eq[OF `0 \<le> floor x`, symmetric]
hoelzl@51523
  2021
    by simp
hoelzl@51523
  2022
qed
hoelzl@51523
  2023
hoelzl@51523
  2024
hoelzl@51523
  2025
subsection {* Implementation of rational real numbers *}
hoelzl@51523
  2026
hoelzl@51523
  2027
text {* Formal constructor *}
hoelzl@51523
  2028
hoelzl@51523
  2029
definition Ratreal :: "rat \<Rightarrow> real" where
hoelzl@51523
  2030
  [code_abbrev, simp]: "Ratreal = of_rat"
hoelzl@51523
  2031
hoelzl@51523
  2032
code_datatype Ratreal
hoelzl@51523
  2033
hoelzl@51523
  2034
hoelzl@51523
  2035
text {* Numerals *}
hoelzl@51523
  2036
hoelzl@51523
  2037
lemma [code_abbrev]:
hoelzl@51523
  2038
  "(of_rat (of_int a) :: real) = of_int a"
hoelzl@51523
  2039
  by simp
hoelzl@51523
  2040
hoelzl@51523
  2041
lemma [code_abbrev]:
hoelzl@51523
  2042
  "(of_rat 0 :: real) = 0"
hoelzl@51523
  2043
  by simp
hoelzl@51523
  2044
hoelzl@51523
  2045
lemma [code_abbrev]:
hoelzl@51523
  2046
  "(of_rat 1 :: real) = 1"
hoelzl@51523
  2047
  by simp
hoelzl@51523
  2048
hoelzl@51523
  2049
lemma [code_abbrev]:
hoelzl@51523
  2050
  "(of_rat (numeral k) :: real) = numeral k"
hoelzl@51523
  2051
  by simp
hoelzl@51523
  2052
hoelzl@51523
  2053
lemma [code_abbrev]:
haftmann@54489
  2054
  "(of_rat (- numeral k) :: real) = - numeral k"
hoelzl@51523
  2055
  by simp
hoelzl@51523
  2056
hoelzl@51523
  2057
lemma [code_post]:
hoelzl@51523
  2058
  "(of_rat (0 / r)  :: real) = 0"
hoelzl@51523
  2059
  "(of_rat (r / 0)  :: real) = 0"
hoelzl@51523
  2060
  "(of_rat (1 / 1)  :: real) = 1"
hoelzl@51523
  2061
  "(of_rat (numeral k / 1) :: real) = numeral k"
haftmann@54489
  2062
  "(of_rat (- numeral k / 1) :: real) = - numeral k"
hoelzl@51523
  2063
  "(of_rat (1 / numeral k) :: real) = 1 / numeral k"
haftmann@54489
  2064
  "(of_rat (1 / - numeral k) :: real) = 1 / - numeral k"
hoelzl@51523
  2065
  "(of_rat (numeral k / numeral l)  :: real) = numeral k / numeral l"
haftmann@54489
  2066
  "(of_rat (numeral k / - numeral l)  :: real) = numeral k / - numeral l"
haftmann@54489
  2067
  "(of_rat (- numeral k / numeral l)  :: real) = - numeral k / numeral l"
haftmann@54489
  2068
  "(of_rat (- numeral k / - numeral l)  :: real) = - numeral k / - numeral l"
haftmann@54489
  2069
  by (simp_all add: of_rat_divide of_rat_minus)
hoelzl@51523
  2070
hoelzl@51523
  2071
hoelzl@51523
  2072
text {* Operations *}
hoelzl@51523
  2073
hoelzl@51523
  2074
lemma zero_real_code [code]:
hoelzl@51523
  2075
  "0 = Ratreal 0"
hoelzl@51523
  2076
by simp
hoelzl@51523
  2077
hoelzl@51523
  2078
lemma one_real_code [code]:
hoelzl@51523
  2079
  "1 = Ratreal 1"
hoelzl@51523
  2080
by simp
hoelzl@51523
  2081
hoelzl@51523
  2082
instantiation real :: equal
hoelzl@51523
  2083
begin
hoelzl@51523
  2084
hoelzl@51523
  2085
definition "HOL.equal (x\<Colon>real) y \<longleftrightarrow> x - y = 0"
hoelzl@51523
  2086
hoelzl@51523
  2087
instance proof
hoelzl@51523
  2088
qed (simp add: equal_real_def)
hoelzl@51523
  2089
hoelzl@51523
  2090
lemma real_equal_code [code]:
hoelzl@51523
  2091
  "HOL.equal (Ratreal x) (Ratreal y) \<longleftrightarrow> HOL.equal x y"
hoelzl@51523
  2092
  by (simp add: equal_real_def equal)
hoelzl@51523
  2093
hoelzl@51523
  2094
lemma [code nbe]:
hoelzl@51523
  2095
  "HOL.equal (x::real) x \<longleftrightarrow> True"
hoelzl@51523
  2096
  by (rule equal_refl)
hoelzl@51523
  2097
hoelzl@51523
  2098
end
hoelzl@51523
  2099
hoelzl@51523
  2100
lemma real_less_eq_code [code]: "Ratreal x \<le> Ratreal y \<longleftrightarrow> x \<le> y"
hoelzl@51523
  2101
  by (simp add: of_rat_less_eq)
hoelzl@51523
  2102
hoelzl@51523
  2103
lemma real_less_code [code]: "Ratreal x < Ratreal y \<longleftrightarrow> x < y"
hoelzl@51523
  2104
  by (simp add: of_rat_less)
hoelzl@51523
  2105
hoelzl@51523
  2106
lemma real_plus_code [code]: "Ratreal x + Ratreal y = Ratreal (x + y)"
hoelzl@51523
  2107
  by (simp add: of_rat_add)
hoelzl@51523
  2108
hoelzl@51523
  2109
lemma real_times_code [code]: "Ratreal x * Ratreal y = Ratreal (x * y)"
hoelzl@51523
  2110
  by (simp add: of_rat_mult)
hoelzl@51523
  2111
hoelzl@51523
  2112
lemma real_uminus_code [code]: "- Ratreal x = Ratreal (- x)"
hoelzl@51523
  2113
  by (simp add: of_rat_minus)
hoelzl@51523
  2114
hoelzl@51523
  2115
lemma real_minus_code [code]: "Ratreal x - Ratreal y = Ratreal (x - y)"
hoelzl@51523
  2116
  by (simp add: of_rat_diff)
hoelzl@51523
  2117
hoelzl@51523
  2118
lemma real_inverse_code [code]: "inverse (Ratreal x) = Ratreal (inverse x)"
hoelzl@51523
  2119
  by (simp add: of_rat_inverse)
hoelzl@51523
  2120
 
hoelzl@51523
  2121
lemma real_divide_code [code]: "Ratreal x / Ratreal y = Ratreal (x / y)"
hoelzl@51523
  2122
  by (simp add: of_rat_divide)
hoelzl@51523
  2123
hoelzl@51523
  2124
lemma real_floor_code [code]: "floor (Ratreal x) = floor x"
hoelzl@51523
  2125
  by (metis Ratreal_def floor_le_iff floor_unique le_floor_iff of_int_floor_le of_rat_of_int_eq real_less_eq_code)
hoelzl@51523
  2126
hoelzl@51523
  2127
hoelzl@51523
  2128
text {* Quickcheck *}
hoelzl@51523
  2129
hoelzl@51523
  2130
definition (in term_syntax)
hoelzl@51523
  2131
  valterm_ratreal :: "rat \<times> (unit \<Rightarrow> Code_Evaluation.term) \<Rightarrow> real \<times> (unit \<Rightarrow> Code_Evaluation.term)" where
hoelzl@51523
  2132
  [code_unfold]: "valterm_ratreal k = Code_Evaluation.valtermify Ratreal {\<cdot>} k"
hoelzl@51523
  2133
hoelzl@51523
  2134
notation fcomp (infixl "\<circ>>" 60)
hoelzl@51523
  2135
notation scomp (infixl "\<circ>\<rightarrow>" 60)
hoelzl@51523
  2136
hoelzl@51523
  2137
instantiation real :: random
hoelzl@51523
  2138
begin
hoelzl@51523
  2139
hoelzl@51523
  2140
definition
hoelzl@51523
  2141
  "Quickcheck_Random.random i = Quickcheck_Random.random i \<circ>\<rightarrow> (\<lambda>r. Pair (valterm_ratreal r))"
hoelzl@51523
  2142
hoelzl@51523
  2143
instance ..
hoelzl@51523
  2144
hoelzl@51523
  2145
end
hoelzl@51523
  2146
hoelzl@51523
  2147
no_notation fcomp (infixl "\<circ>>" 60)
hoelzl@51523
  2148
no_notation scomp (infixl "\<circ>\<rightarrow>" 60)
hoelzl@51523
  2149
hoelzl@51523
  2150
instantiation real :: exhaustive
hoelzl@51523
  2151
begin
hoelzl@51523
  2152
hoelzl@51523
  2153
definition
hoelzl@51523
  2154
  "exhaustive_real f d = Quickcheck_Exhaustive.exhaustive (%r. f (Ratreal r)) d"
hoelzl@51523
  2155
hoelzl@51523
  2156
instance ..
hoelzl@51523
  2157
hoelzl@51523
  2158
end
hoelzl@51523
  2159
hoelzl@51523
  2160
instantiation real :: full_exhaustive
hoelzl@51523
  2161
begin
hoelzl@51523
  2162
hoelzl@51523
  2163
definition
hoelzl@51523
  2164
  "full_exhaustive_real f d = Quickcheck_Exhaustive.full_exhaustive (%r. f (valterm_ratreal r)) d"
hoelzl@51523
  2165
hoelzl@51523
  2166
instance ..
hoelzl@51523
  2167
hoelzl@51523
  2168
end
hoelzl@51523
  2169
hoelzl@51523
  2170
instantiation real :: narrowing
hoelzl@51523
  2171
begin
hoelzl@51523
  2172
hoelzl@51523
  2173
definition
hoelzl@51523
  2174
  "narrowing = Quickcheck_Narrowing.apply (Quickcheck_Narrowing.cons Ratreal) narrowing"
hoelzl@51523
  2175
hoelzl@51523
  2176
instance ..
hoelzl@51523
  2177
hoelzl@51523
  2178
end
hoelzl@51523
  2179
hoelzl@51523
  2180
hoelzl@51523
  2181
subsection {* Setup for Nitpick *}
hoelzl@51523
  2182
hoelzl@51523
  2183
declaration {*
hoelzl@51523
  2184
  Nitpick_HOL.register_frac_type @{type_name real}
hoelzl@51523
  2185
   [(@{const_name zero_real_inst.zero_real}, @{const_name Nitpick.zero_frac}),
hoelzl@51523
  2186
    (@{const_name one_real_inst.one_real}, @{const_name Nitpick.one_frac}),
hoelzl@51523
  2187
    (@{const_name plus_real_inst.plus_real}, @{const_name Nitpick.plus_frac}),
hoelzl@51523
  2188
    (@{const_name times_real_inst.times_real}, @{const_name Nitpick.times_frac}),
hoelzl@51523
  2189
    (@{const_name uminus_real_inst.uminus_real}, @{const_name Nitpick.uminus_frac}),
hoelzl@51523
  2190
    (@{const_name inverse_real_inst.inverse_real}, @{const_name Nitpick.inverse_frac}),
hoelzl@51523
  2191
    (@{const_name ord_real_inst.less_real}, @{const_name Nitpick.less_frac}),
hoelzl@51523
  2192
    (@{const_name ord_real_inst.less_eq_real}, @{const_name Nitpick.less_eq_frac})]
hoelzl@51523
  2193
*}
hoelzl@51523
  2194
hoelzl@51523
  2195
lemmas [nitpick_unfold] = inverse_real_inst.inverse_real one_real_inst.one_real
hoelzl@51523
  2196
    ord_real_inst.less_real ord_real_inst.less_eq_real plus_real_inst.plus_real
hoelzl@51523
  2197
    times_real_inst.times_real uminus_real_inst.uminus_real
hoelzl@51523
  2198
    zero_real_inst.zero_real
hoelzl@51523
  2199
hoelzl@51523
  2200
ML_file "Tools/SMT/smt_real.ML"
hoelzl@51523
  2201
setup SMT_Real.setup
hoelzl@51523
  2202
hoelzl@51523
  2203
end