src/HOL/Set_Interval.thy
author wenzelm
Sun Sep 18 20:33:48 2016 +0200 (2016-09-18)
changeset 63915 bab633745c7f
parent 63879 15bbf6360339
child 63918 6bf55e6e0b75
permissions -rw-r--r--
tuned proofs;
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(*  Title:      HOL/Set_Interval.thy
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    Author:     Tobias Nipkow
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    Author:     Clemens Ballarin
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    Author:     Jeremy Avigad
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lessThan, greaterThan, atLeast, atMost and two-sided intervals
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Modern convention: Ixy stands for an interval where x and y
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describe the lower and upper bound and x,y : {c,o,i}
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where c = closed, o = open, i = infinite.
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Examples: Ico = {_ ..< _} and Ici = {_ ..}
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*)
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section \<open>Set intervals\<close>
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theory Set_Interval
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imports Lattices_Big Divides Nat_Transfer
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begin
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context ord
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begin
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definition
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  lessThan    :: "'a => 'a set" ("(1{..<_})") where
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  "{..<u} == {x. x < u}"
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definition
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  atMost      :: "'a => 'a set" ("(1{.._})") where
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  "{..u} == {x. x \<le> u}"
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definition
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  greaterThan :: "'a => 'a set" ("(1{_<..})") where
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  "{l<..} == {x. l<x}"
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definition
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  atLeast     :: "'a => 'a set" ("(1{_..})") where
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  "{l..} == {x. l\<le>x}"
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definition
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  greaterThanLessThan :: "'a => 'a => 'a set"  ("(1{_<..<_})") where
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  "{l<..<u} == {l<..} Int {..<u}"
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definition
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  atLeastLessThan :: "'a => 'a => 'a set"      ("(1{_..<_})") where
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  "{l..<u} == {l..} Int {..<u}"
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definition
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  greaterThanAtMost :: "'a => 'a => 'a set"    ("(1{_<.._})") where
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  "{l<..u} == {l<..} Int {..u}"
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definition
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  atLeastAtMost :: "'a => 'a => 'a set"        ("(1{_.._})") where
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  "{l..u} == {l..} Int {..u}"
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end
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text\<open>A note of warning when using @{term"{..<n}"} on type @{typ
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nat}: it is equivalent to @{term"{0::nat..<n}"} but some lemmas involving
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@{term"{m..<n}"} may not exist in @{term"{..<n}"}-form as well.\<close>
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syntax (ASCII)
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  "_UNION_le"   :: "'a => 'a => 'b set => 'b set"       ("(3UN _<=_./ _)" [0, 0, 10] 10)
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  "_UNION_less" :: "'a => 'a => 'b set => 'b set"       ("(3UN _<_./ _)" [0, 0, 10] 10)
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  "_INTER_le"   :: "'a => 'a => 'b set => 'b set"       ("(3INT _<=_./ _)" [0, 0, 10] 10)
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  "_INTER_less" :: "'a => 'a => 'b set => 'b set"       ("(3INT _<_./ _)" [0, 0, 10] 10)
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syntax (latex output)
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  "_UNION_le"   :: "'a \<Rightarrow> 'a => 'b set => 'b set"       ("(3\<Union>(\<open>unbreakable\<close>_ \<le> _)/ _)" [0, 0, 10] 10)
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  "_UNION_less" :: "'a \<Rightarrow> 'a => 'b set => 'b set"       ("(3\<Union>(\<open>unbreakable\<close>_ < _)/ _)" [0, 0, 10] 10)
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  "_INTER_le"   :: "'a \<Rightarrow> 'a => 'b set => 'b set"       ("(3\<Inter>(\<open>unbreakable\<close>_ \<le> _)/ _)" [0, 0, 10] 10)
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  "_INTER_less" :: "'a \<Rightarrow> 'a => 'b set => 'b set"       ("(3\<Inter>(\<open>unbreakable\<close>_ < _)/ _)" [0, 0, 10] 10)
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syntax
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  "_UNION_le"   :: "'a => 'a => 'b set => 'b set"       ("(3\<Union>_\<le>_./ _)" [0, 0, 10] 10)
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  "_UNION_less" :: "'a => 'a => 'b set => 'b set"       ("(3\<Union>_<_./ _)" [0, 0, 10] 10)
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  "_INTER_le"   :: "'a => 'a => 'b set => 'b set"       ("(3\<Inter>_\<le>_./ _)" [0, 0, 10] 10)
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  "_INTER_less" :: "'a => 'a => 'b set => 'b set"       ("(3\<Inter>_<_./ _)" [0, 0, 10] 10)
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translations
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  "\<Union>i\<le>n. A" \<rightleftharpoons> "\<Union>i\<in>{..n}. A"
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  "\<Union>i<n. A" \<rightleftharpoons> "\<Union>i\<in>{..<n}. A"
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  "\<Inter>i\<le>n. A" \<rightleftharpoons> "\<Inter>i\<in>{..n}. A"
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  "\<Inter>i<n. A" \<rightleftharpoons> "\<Inter>i\<in>{..<n}. A"
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subsection \<open>Various equivalences\<close>
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lemma (in ord) lessThan_iff [iff]: "(i: lessThan k) = (i<k)"
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by (simp add: lessThan_def)
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lemma Compl_lessThan [simp]:
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    "!!k:: 'a::linorder. -lessThan k = atLeast k"
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apply (auto simp add: lessThan_def atLeast_def)
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done
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lemma single_Diff_lessThan [simp]: "!!k:: 'a::order. {k} - lessThan k = {k}"
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by auto
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lemma (in ord) greaterThan_iff [iff]: "(i: greaterThan k) = (k<i)"
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by (simp add: greaterThan_def)
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lemma Compl_greaterThan [simp]:
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    "!!k:: 'a::linorder. -greaterThan k = atMost k"
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  by (auto simp add: greaterThan_def atMost_def)
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lemma Compl_atMost [simp]: "!!k:: 'a::linorder. -atMost k = greaterThan k"
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apply (subst Compl_greaterThan [symmetric])
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apply (rule double_complement)
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done
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lemma (in ord) atLeast_iff [iff]: "(i: atLeast k) = (k<=i)"
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by (simp add: atLeast_def)
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lemma Compl_atLeast [simp]:
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    "!!k:: 'a::linorder. -atLeast k = lessThan k"
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  by (auto simp add: lessThan_def atLeast_def)
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lemma (in ord) atMost_iff [iff]: "(i: atMost k) = (i<=k)"
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by (simp add: atMost_def)
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lemma atMost_Int_atLeast: "!!n:: 'a::order. atMost n Int atLeast n = {n}"
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by (blast intro: order_antisym)
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lemma (in linorder) lessThan_Int_lessThan: "{ a <..} \<inter> { b <..} = { max a b <..}"
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  by auto
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lemma (in linorder) greaterThan_Int_greaterThan: "{..< a} \<inter> {..< b} = {..< min a b}"
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  by auto
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subsection \<open>Logical Equivalences for Set Inclusion and Equality\<close>
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lemma atLeast_empty_triv [simp]: "{{}..} = UNIV"
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  by auto
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lemma atMost_UNIV_triv [simp]: "{..UNIV} = UNIV"
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  by auto
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lemma atLeast_subset_iff [iff]:
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     "(atLeast x \<subseteq> atLeast y) = (y \<le> (x::'a::order))"
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by (blast intro: order_trans)
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lemma atLeast_eq_iff [iff]:
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     "(atLeast x = atLeast y) = (x = (y::'a::linorder))"
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by (blast intro: order_antisym order_trans)
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lemma greaterThan_subset_iff [iff]:
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     "(greaterThan x \<subseteq> greaterThan y) = (y \<le> (x::'a::linorder))"
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apply (auto simp add: greaterThan_def)
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 apply (subst linorder_not_less [symmetric], blast)
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done
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lemma greaterThan_eq_iff [iff]:
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     "(greaterThan x = greaterThan y) = (x = (y::'a::linorder))"
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apply (rule iffI)
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 apply (erule equalityE)
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 apply simp_all
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done
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lemma atMost_subset_iff [iff]: "(atMost x \<subseteq> atMost y) = (x \<le> (y::'a::order))"
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by (blast intro: order_trans)
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lemma atMost_eq_iff [iff]: "(atMost x = atMost y) = (x = (y::'a::linorder))"
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by (blast intro: order_antisym order_trans)
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lemma lessThan_subset_iff [iff]:
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     "(lessThan x \<subseteq> lessThan y) = (x \<le> (y::'a::linorder))"
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apply (auto simp add: lessThan_def)
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 apply (subst linorder_not_less [symmetric], blast)
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done
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lemma lessThan_eq_iff [iff]:
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     "(lessThan x = lessThan y) = (x = (y::'a::linorder))"
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apply (rule iffI)
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 apply (erule equalityE)
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 apply simp_all
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done
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lemma lessThan_strict_subset_iff:
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  fixes m n :: "'a::linorder"
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  shows "{..<m} < {..<n} \<longleftrightarrow> m < n"
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  by (metis leD lessThan_subset_iff linorder_linear not_less_iff_gr_or_eq psubset_eq)
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lemma (in linorder) Ici_subset_Ioi_iff: "{a ..} \<subseteq> {b <..} \<longleftrightarrow> b < a"
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  by auto
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lemma (in linorder) Iic_subset_Iio_iff: "{.. a} \<subseteq> {..< b} \<longleftrightarrow> a < b"
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  by auto
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lemma (in preorder) Ioi_le_Ico: "{a <..} \<subseteq> {a ..}"
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  by (auto intro: less_imp_le)
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subsection \<open>Two-sided intervals\<close>
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context ord
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begin
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lemma greaterThanLessThan_iff [simp]:
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  "(i : {l<..<u}) = (l < i & i < u)"
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by (simp add: greaterThanLessThan_def)
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lemma atLeastLessThan_iff [simp]:
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  "(i : {l..<u}) = (l <= i & i < u)"
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by (simp add: atLeastLessThan_def)
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lemma greaterThanAtMost_iff [simp]:
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  "(i : {l<..u}) = (l < i & i <= u)"
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by (simp add: greaterThanAtMost_def)
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lemma atLeastAtMost_iff [simp]:
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  "(i : {l..u}) = (l <= i & i <= u)"
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by (simp add: atLeastAtMost_def)
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text \<open>The above four lemmas could be declared as iffs. Unfortunately this
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breaks many proofs. Since it only helps blast, it is better to leave them
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alone.\<close>
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lemma greaterThanLessThan_eq: "{ a <..< b} = { a <..} \<inter> {..< b }"
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  by auto
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end
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subsubsection\<open>Emptyness, singletons, subset\<close>
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context order
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begin
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lemma atLeastatMost_empty[simp]:
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  "b < a \<Longrightarrow> {a..b} = {}"
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by(auto simp: atLeastAtMost_def atLeast_def atMost_def)
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lemma atLeastatMost_empty_iff[simp]:
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  "{a..b} = {} \<longleftrightarrow> (~ a <= b)"
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by auto (blast intro: order_trans)
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lemma atLeastatMost_empty_iff2[simp]:
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  "{} = {a..b} \<longleftrightarrow> (~ a <= b)"
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by auto (blast intro: order_trans)
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lemma atLeastLessThan_empty[simp]:
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  "b <= a \<Longrightarrow> {a..<b} = {}"
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by(auto simp: atLeastLessThan_def)
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lemma atLeastLessThan_empty_iff[simp]:
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  "{a..<b} = {} \<longleftrightarrow> (~ a < b)"
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by auto (blast intro: le_less_trans)
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lemma atLeastLessThan_empty_iff2[simp]:
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  "{} = {a..<b} \<longleftrightarrow> (~ a < b)"
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by auto (blast intro: le_less_trans)
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lemma greaterThanAtMost_empty[simp]: "l \<le> k ==> {k<..l} = {}"
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by(auto simp:greaterThanAtMost_def greaterThan_def atMost_def)
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lemma greaterThanAtMost_empty_iff[simp]: "{k<..l} = {} \<longleftrightarrow> ~ k < l"
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by auto (blast intro: less_le_trans)
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lemma greaterThanAtMost_empty_iff2[simp]: "{} = {k<..l} \<longleftrightarrow> ~ k < l"
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by auto (blast intro: less_le_trans)
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lemma greaterThanLessThan_empty[simp]:"l \<le> k ==> {k<..<l} = {}"
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by(auto simp:greaterThanLessThan_def greaterThan_def lessThan_def)
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lemma atLeastAtMost_singleton [simp]: "{a..a} = {a}"
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by (auto simp add: atLeastAtMost_def atMost_def atLeast_def)
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lemma atLeastAtMost_singleton': "a = b \<Longrightarrow> {a .. b} = {a}" by simp
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lemma atLeastatMost_subset_iff[simp]:
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  "{a..b} <= {c..d} \<longleftrightarrow> (~ a <= b) | c <= a & b <= d"
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unfolding atLeastAtMost_def atLeast_def atMost_def
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by (blast intro: order_trans)
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lemma atLeastatMost_psubset_iff:
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  "{a..b} < {c..d} \<longleftrightarrow>
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   ((~ a <= b) | c <= a & b <= d & (c < a | b < d))  &  c <= d"
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by(simp add: psubset_eq set_eq_iff less_le_not_le)(blast intro: order_trans)
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lemma Icc_eq_Icc[simp]:
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  "{l..h} = {l'..h'} = (l=l' \<and> h=h' \<or> \<not> l\<le>h \<and> \<not> l'\<le>h')"
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by(simp add: order_class.eq_iff)(auto intro: order_trans)
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lemma atLeastAtMost_singleton_iff[simp]:
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  "{a .. b} = {c} \<longleftrightarrow> a = b \<and> b = c"
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proof
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  assume "{a..b} = {c}"
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  hence *: "\<not> (\<not> a \<le> b)" unfolding atLeastatMost_empty_iff[symmetric] by simp
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  with \<open>{a..b} = {c}\<close> have "c \<le> a \<and> b \<le> c" by auto
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  with * show "a = b \<and> b = c" by auto
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qed simp
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lemma Icc_subset_Ici_iff[simp]:
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  "{l..h} \<subseteq> {l'..} = (~ l\<le>h \<or> l\<ge>l')"
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by(auto simp: subset_eq intro: order_trans)
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lemma Icc_subset_Iic_iff[simp]:
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  "{l..h} \<subseteq> {..h'} = (~ l\<le>h \<or> h\<le>h')"
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by(auto simp: subset_eq intro: order_trans)
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lemma not_Ici_eq_empty[simp]: "{l..} \<noteq> {}"
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by(auto simp: set_eq_iff)
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lemma not_Iic_eq_empty[simp]: "{..h} \<noteq> {}"
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by(auto simp: set_eq_iff)
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lemmas not_empty_eq_Ici_eq_empty[simp] = not_Ici_eq_empty[symmetric]
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lemmas not_empty_eq_Iic_eq_empty[simp] = not_Iic_eq_empty[symmetric]
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end
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context no_top
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begin
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(* also holds for no_bot but no_top should suffice *)
nipkow@51334
   315
lemma not_UNIV_le_Icc[simp]: "\<not> UNIV \<subseteq> {l..h}"
nipkow@51334
   316
using gt_ex[of h] by(auto simp: subset_eq less_le_not_le)
nipkow@51334
   317
nipkow@51334
   318
lemma not_UNIV_le_Iic[simp]: "\<not> UNIV \<subseteq> {..h}"
nipkow@51334
   319
using gt_ex[of h] by(auto simp: subset_eq less_le_not_le)
nipkow@51334
   320
nipkow@51334
   321
lemma not_Ici_le_Icc[simp]: "\<not> {l..} \<subseteq> {l'..h'}"
nipkow@51334
   322
using gt_ex[of h']
nipkow@51334
   323
by(auto simp: subset_eq less_le)(blast dest:antisym_conv intro: order_trans)
nipkow@51334
   324
nipkow@51334
   325
lemma not_Ici_le_Iic[simp]: "\<not> {l..} \<subseteq> {..h'}"
nipkow@51334
   326
using gt_ex[of h']
nipkow@51334
   327
by(auto simp: subset_eq less_le)(blast dest:antisym_conv intro: order_trans)
nipkow@51334
   328
nipkow@51334
   329
end
nipkow@51334
   330
nipkow@51334
   331
context no_bot
nipkow@51334
   332
begin
nipkow@51334
   333
nipkow@51334
   334
lemma not_UNIV_le_Ici[simp]: "\<not> UNIV \<subseteq> {l..}"
nipkow@51334
   335
using lt_ex[of l] by(auto simp: subset_eq less_le_not_le)
nipkow@51334
   336
nipkow@51334
   337
lemma not_Iic_le_Icc[simp]: "\<not> {..h} \<subseteq> {l'..h'}"
nipkow@51334
   338
using lt_ex[of l']
nipkow@51334
   339
by(auto simp: subset_eq less_le)(blast dest:antisym_conv intro: order_trans)
nipkow@51334
   340
nipkow@51334
   341
lemma not_Iic_le_Ici[simp]: "\<not> {..h} \<subseteq> {l'..}"
nipkow@51334
   342
using lt_ex[of l']
nipkow@51334
   343
by(auto simp: subset_eq less_le)(blast dest:antisym_conv intro: order_trans)
nipkow@51334
   344
nipkow@51334
   345
end
nipkow@51334
   346
nipkow@51334
   347
nipkow@51334
   348
context no_top
nipkow@51334
   349
begin
nipkow@51334
   350
nipkow@51334
   351
(* also holds for no_bot but no_top should suffice *)
nipkow@51334
   352
lemma not_UNIV_eq_Icc[simp]: "\<not> UNIV = {l'..h'}"
nipkow@51334
   353
using gt_ex[of h'] by(auto simp: set_eq_iff  less_le_not_le)
nipkow@51334
   354
nipkow@51334
   355
lemmas not_Icc_eq_UNIV[simp] = not_UNIV_eq_Icc[symmetric]
nipkow@51334
   356
nipkow@51334
   357
lemma not_UNIV_eq_Iic[simp]: "\<not> UNIV = {..h'}"
nipkow@51334
   358
using gt_ex[of h'] by(auto simp: set_eq_iff  less_le_not_le)
nipkow@51334
   359
nipkow@51334
   360
lemmas not_Iic_eq_UNIV[simp] = not_UNIV_eq_Iic[symmetric]
nipkow@51334
   361
nipkow@51334
   362
lemma not_Icc_eq_Ici[simp]: "\<not> {l..h} = {l'..}"
nipkow@51334
   363
unfolding atLeastAtMost_def using not_Ici_le_Iic[of l'] by blast
nipkow@51334
   364
nipkow@51334
   365
lemmas not_Ici_eq_Icc[simp] = not_Icc_eq_Ici[symmetric]
nipkow@51334
   366
nipkow@51334
   367
(* also holds for no_bot but no_top should suffice *)
nipkow@51334
   368
lemma not_Iic_eq_Ici[simp]: "\<not> {..h} = {l'..}"
nipkow@51334
   369
using not_Ici_le_Iic[of l' h] by blast
nipkow@51334
   370
nipkow@51334
   371
lemmas not_Ici_eq_Iic[simp] = not_Iic_eq_Ici[symmetric]
nipkow@51334
   372
nipkow@51334
   373
end
nipkow@51334
   374
nipkow@51334
   375
context no_bot
nipkow@51334
   376
begin
nipkow@51334
   377
nipkow@51334
   378
lemma not_UNIV_eq_Ici[simp]: "\<not> UNIV = {l'..}"
nipkow@51334
   379
using lt_ex[of l'] by(auto simp: set_eq_iff  less_le_not_le)
nipkow@51334
   380
nipkow@51334
   381
lemmas not_Ici_eq_UNIV[simp] = not_UNIV_eq_Ici[symmetric]
nipkow@51334
   382
nipkow@51334
   383
lemma not_Icc_eq_Iic[simp]: "\<not> {l..h} = {..h'}"
nipkow@51334
   384
unfolding atLeastAtMost_def using not_Iic_le_Ici[of h'] by blast
nipkow@51334
   385
nipkow@51334
   386
lemmas not_Iic_eq_Icc[simp] = not_Icc_eq_Iic[symmetric]
nipkow@51334
   387
nipkow@51334
   388
end
nipkow@51334
   389
nipkow@51334
   390
hoelzl@53216
   391
context dense_linorder
hoelzl@42891
   392
begin
hoelzl@42891
   393
hoelzl@42891
   394
lemma greaterThanLessThan_empty_iff[simp]:
hoelzl@42891
   395
  "{ a <..< b } = {} \<longleftrightarrow> b \<le> a"
hoelzl@42891
   396
  using dense[of a b] by (cases "a < b") auto
hoelzl@42891
   397
hoelzl@42891
   398
lemma greaterThanLessThan_empty_iff2[simp]:
hoelzl@42891
   399
  "{} = { a <..< b } \<longleftrightarrow> b \<le> a"
hoelzl@42891
   400
  using dense[of a b] by (cases "a < b") auto
hoelzl@42891
   401
hoelzl@42901
   402
lemma atLeastLessThan_subseteq_atLeastAtMost_iff:
hoelzl@42901
   403
  "{a ..< b} \<subseteq> { c .. d } \<longleftrightarrow> (a < b \<longrightarrow> c \<le> a \<and> b \<le> d)"
hoelzl@42901
   404
  using dense[of "max a d" "b"]
hoelzl@42901
   405
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@42901
   406
hoelzl@42901
   407
lemma greaterThanAtMost_subseteq_atLeastAtMost_iff:
hoelzl@42901
   408
  "{a <.. b} \<subseteq> { c .. d } \<longleftrightarrow> (a < b \<longrightarrow> c \<le> a \<and> b \<le> d)"
hoelzl@42901
   409
  using dense[of "a" "min c b"]
hoelzl@42901
   410
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@42901
   411
hoelzl@42901
   412
lemma greaterThanLessThan_subseteq_atLeastAtMost_iff:
hoelzl@42901
   413
  "{a <..< b} \<subseteq> { c .. d } \<longleftrightarrow> (a < b \<longrightarrow> c \<le> a \<and> b \<le> d)"
hoelzl@42901
   414
  using dense[of "a" "min c b"] dense[of "max a d" "b"]
hoelzl@42901
   415
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@42901
   416
hoelzl@43657
   417
lemma atLeastAtMost_subseteq_atLeastLessThan_iff:
hoelzl@43657
   418
  "{a .. b} \<subseteq> { c ..< d } \<longleftrightarrow> (a \<le> b \<longrightarrow> c \<le> a \<and> b < d)"
hoelzl@43657
   419
  using dense[of "max a d" "b"]
hoelzl@43657
   420
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@62369
   421
eberlm@61524
   422
lemma greaterThanLessThan_subseteq_greaterThanLessThan:
eberlm@61524
   423
  "{a <..< b} \<subseteq> {c <..< d} \<longleftrightarrow> (a < b \<longrightarrow> a \<ge> c \<and> b \<le> d)"
eberlm@61524
   424
  using dense[of "a" "min c b"] dense[of "max a d" "b"]
eberlm@61524
   425
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@43657
   426
hoelzl@43657
   427
lemma greaterThanAtMost_subseteq_atLeastLessThan_iff:
hoelzl@43657
   428
  "{a <.. b} \<subseteq> { c ..< d } \<longleftrightarrow> (a < b \<longrightarrow> c \<le> a \<and> b < d)"
hoelzl@43657
   429
  using dense[of "a" "min c b"]
hoelzl@43657
   430
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@43657
   431
hoelzl@43657
   432
lemma greaterThanLessThan_subseteq_atLeastLessThan_iff:
hoelzl@43657
   433
  "{a <..< b} \<subseteq> { c ..< d } \<longleftrightarrow> (a < b \<longrightarrow> c \<le> a \<and> b \<le> d)"
hoelzl@43657
   434
  using dense[of "a" "min c b"] dense[of "max a d" "b"]
hoelzl@43657
   435
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@43657
   436
hoelzl@56328
   437
lemma greaterThanLessThan_subseteq_greaterThanAtMost_iff:
hoelzl@56328
   438
  "{a <..< b} \<subseteq> { c <.. d } \<longleftrightarrow> (a < b \<longrightarrow> c \<le> a \<and> b \<le> d)"
hoelzl@56328
   439
  using dense[of "a" "min c b"] dense[of "max a d" "b"]
hoelzl@56328
   440
  by (force simp: subset_eq Ball_def not_less[symmetric])
hoelzl@56328
   441
hoelzl@42891
   442
end
hoelzl@42891
   443
hoelzl@51329
   444
context no_top
hoelzl@51329
   445
begin
hoelzl@51329
   446
nipkow@51334
   447
lemma greaterThan_non_empty[simp]: "{x <..} \<noteq> {}"
hoelzl@51329
   448
  using gt_ex[of x] by auto
hoelzl@51329
   449
hoelzl@51329
   450
end
hoelzl@51329
   451
hoelzl@51329
   452
context no_bot
hoelzl@51329
   453
begin
hoelzl@51329
   454
nipkow@51334
   455
lemma lessThan_non_empty[simp]: "{..< x} \<noteq> {}"
hoelzl@51329
   456
  using lt_ex[of x] by auto
hoelzl@51329
   457
hoelzl@51329
   458
end
hoelzl@51329
   459
nipkow@32408
   460
lemma (in linorder) atLeastLessThan_subset_iff:
nipkow@32408
   461
  "{a..<b} <= {c..<d} \<Longrightarrow> b <= a | c<=a & b<=d"
nipkow@32408
   462
apply (auto simp:subset_eq Ball_def)
nipkow@32408
   463
apply(frule_tac x=a in spec)
nipkow@32408
   464
apply(erule_tac x=d in allE)
nipkow@32408
   465
apply (simp add: less_imp_le)
nipkow@32408
   466
done
nipkow@32408
   467
hoelzl@40703
   468
lemma atLeastLessThan_inj:
hoelzl@40703
   469
  fixes a b c d :: "'a::linorder"
hoelzl@40703
   470
  assumes eq: "{a ..< b} = {c ..< d}" and "a < b" "c < d"
hoelzl@40703
   471
  shows "a = c" "b = d"
hoelzl@40703
   472
using assms by (metis atLeastLessThan_subset_iff eq less_le_not_le linorder_antisym_conv2 subset_refl)+
hoelzl@40703
   473
hoelzl@40703
   474
lemma atLeastLessThan_eq_iff:
hoelzl@40703
   475
  fixes a b c d :: "'a::linorder"
hoelzl@40703
   476
  assumes "a < b" "c < d"
hoelzl@40703
   477
  shows "{a ..< b} = {c ..< d} \<longleftrightarrow> a = c \<and> b = d"
hoelzl@40703
   478
  using atLeastLessThan_inj assms by auto
hoelzl@40703
   479
hoelzl@57447
   480
lemma (in linorder) Ioc_inj: "{a <.. b} = {c <.. d} \<longleftrightarrow> (b \<le> a \<and> d \<le> c) \<or> a = c \<and> b = d"
hoelzl@57447
   481
  by (metis eq_iff greaterThanAtMost_empty_iff2 greaterThanAtMost_iff le_cases not_le)
hoelzl@57447
   482
hoelzl@57447
   483
lemma (in order) Iio_Int_singleton: "{..<k} \<inter> {x} = (if x < k then {x} else {})"
hoelzl@57447
   484
  by auto
hoelzl@57447
   485
hoelzl@57447
   486
lemma (in linorder) Ioc_subset_iff: "{a<..b} \<subseteq> {c<..d} \<longleftrightarrow> (b \<le> a \<or> c \<le> a \<and> b \<le> d)"
hoelzl@57447
   487
  by (auto simp: subset_eq Ball_def) (metis less_le not_less)
hoelzl@57447
   488
haftmann@52729
   489
lemma (in order_bot) atLeast_eq_UNIV_iff: "{x..} = UNIV \<longleftrightarrow> x = bot"
nipkow@51334
   490
by (auto simp: set_eq_iff intro: le_bot)
hoelzl@51328
   491
haftmann@52729
   492
lemma (in order_top) atMost_eq_UNIV_iff: "{..x} = UNIV \<longleftrightarrow> x = top"
nipkow@51334
   493
by (auto simp: set_eq_iff intro: top_le)
hoelzl@51328
   494
nipkow@51334
   495
lemma (in bounded_lattice) atLeastAtMost_eq_UNIV_iff:
nipkow@51334
   496
  "{x..y} = UNIV \<longleftrightarrow> (x = bot \<and> y = top)"
nipkow@51334
   497
by (auto simp: set_eq_iff intro: top_le le_bot)
hoelzl@51328
   498
hoelzl@56949
   499
lemma Iio_eq_empty_iff: "{..< n::'a::{linorder, order_bot}} = {} \<longleftrightarrow> n = bot"
hoelzl@56949
   500
  by (auto simp: set_eq_iff not_less le_bot)
hoelzl@56949
   501
hoelzl@56949
   502
lemma Iio_eq_empty_iff_nat: "{..< n::nat} = {} \<longleftrightarrow> n = 0"
hoelzl@56949
   503
  by (simp add: Iio_eq_empty_iff bot_nat_def)
hoelzl@56949
   504
noschinl@58970
   505
lemma mono_image_least:
noschinl@58970
   506
  assumes f_mono: "mono f" and f_img: "f ` {m ..< n} = {m' ..< n'}" "m < n"
noschinl@58970
   507
  shows "f m = m'"
noschinl@58970
   508
proof -
noschinl@58970
   509
  from f_img have "{m' ..< n'} \<noteq> {}"
noschinl@58970
   510
    by (metis atLeastLessThan_empty_iff image_is_empty)
noschinl@58970
   511
  with f_img have "m' \<in> f ` {m ..< n}" by auto
noschinl@58970
   512
  then obtain k where "f k = m'" "m \<le> k" by auto
noschinl@58970
   513
  moreover have "m' \<le> f m" using f_img by auto
noschinl@58970
   514
  ultimately show "f m = m'"
noschinl@58970
   515
    using f_mono by (auto elim: monoE[where x=m and y=k])
noschinl@58970
   516
qed
noschinl@58970
   517
hoelzl@51328
   518
wenzelm@60758
   519
subsection \<open>Infinite intervals\<close>
hoelzl@56328
   520
hoelzl@56328
   521
context dense_linorder
hoelzl@56328
   522
begin
hoelzl@56328
   523
hoelzl@56328
   524
lemma infinite_Ioo:
hoelzl@56328
   525
  assumes "a < b"
hoelzl@56328
   526
  shows "\<not> finite {a<..<b}"
hoelzl@56328
   527
proof
hoelzl@56328
   528
  assume fin: "finite {a<..<b}"
hoelzl@56328
   529
  moreover have ne: "{a<..<b} \<noteq> {}"
wenzelm@60758
   530
    using \<open>a < b\<close> by auto
hoelzl@56328
   531
  ultimately have "a < Max {a <..< b}" "Max {a <..< b} < b"
hoelzl@56328
   532
    using Max_in[of "{a <..< b}"] by auto
hoelzl@56328
   533
  then obtain x where "Max {a <..< b} < x" "x < b"
hoelzl@56328
   534
    using dense[of "Max {a<..<b}" b] by auto
hoelzl@56328
   535
  then have "x \<in> {a <..< b}"
wenzelm@60758
   536
    using \<open>a < Max {a <..< b}\<close> by auto
hoelzl@56328
   537
  then have "x \<le> Max {a <..< b}"
hoelzl@56328
   538
    using fin by auto
wenzelm@60758
   539
  with \<open>Max {a <..< b} < x\<close> show False by auto
hoelzl@56328
   540
qed
hoelzl@56328
   541
hoelzl@56328
   542
lemma infinite_Icc: "a < b \<Longrightarrow> \<not> finite {a .. b}"
hoelzl@56328
   543
  using greaterThanLessThan_subseteq_atLeastAtMost_iff[of a b a b] infinite_Ioo[of a b]
hoelzl@56328
   544
  by (auto dest: finite_subset)
hoelzl@56328
   545
hoelzl@56328
   546
lemma infinite_Ico: "a < b \<Longrightarrow> \<not> finite {a ..< b}"
hoelzl@56328
   547
  using greaterThanLessThan_subseteq_atLeastLessThan_iff[of a b a b] infinite_Ioo[of a b]
hoelzl@56328
   548
  by (auto dest: finite_subset)
hoelzl@56328
   549
hoelzl@56328
   550
lemma infinite_Ioc: "a < b \<Longrightarrow> \<not> finite {a <.. b}"
hoelzl@56328
   551
  using greaterThanLessThan_subseteq_greaterThanAtMost_iff[of a b a b] infinite_Ioo[of a b]
hoelzl@56328
   552
  by (auto dest: finite_subset)
hoelzl@56328
   553
hoelzl@56328
   554
end
hoelzl@56328
   555
hoelzl@56328
   556
lemma infinite_Iio: "\<not> finite {..< a :: 'a :: {no_bot, linorder}}"
hoelzl@56328
   557
proof
hoelzl@56328
   558
  assume "finite {..< a}"
hoelzl@56328
   559
  then have *: "\<And>x. x < a \<Longrightarrow> Min {..< a} \<le> x"
hoelzl@56328
   560
    by auto
hoelzl@56328
   561
  obtain x where "x < a"
hoelzl@56328
   562
    using lt_ex by auto
hoelzl@56328
   563
hoelzl@56328
   564
  obtain y where "y < Min {..< a}"
hoelzl@56328
   565
    using lt_ex by auto
hoelzl@56328
   566
  also have "Min {..< a} \<le> x"
wenzelm@60758
   567
    using \<open>x < a\<close> by fact
wenzelm@60758
   568
  also note \<open>x < a\<close>
hoelzl@56328
   569
  finally have "Min {..< a} \<le> y"
hoelzl@56328
   570
    by fact
wenzelm@60758
   571
  with \<open>y < Min {..< a}\<close> show False by auto
hoelzl@56328
   572
qed
hoelzl@56328
   573
hoelzl@56328
   574
lemma infinite_Iic: "\<not> finite {.. a :: 'a :: {no_bot, linorder}}"
hoelzl@56328
   575
  using infinite_Iio[of a] finite_subset[of "{..< a}" "{.. a}"]
hoelzl@56328
   576
  by (auto simp: subset_eq less_imp_le)
hoelzl@56328
   577
hoelzl@56328
   578
lemma infinite_Ioi: "\<not> finite {a :: 'a :: {no_top, linorder} <..}"
hoelzl@56328
   579
proof
hoelzl@56328
   580
  assume "finite {a <..}"
hoelzl@56328
   581
  then have *: "\<And>x. a < x \<Longrightarrow> x \<le> Max {a <..}"
hoelzl@56328
   582
    by auto
hoelzl@56328
   583
hoelzl@56328
   584
  obtain y where "Max {a <..} < y"
hoelzl@56328
   585
    using gt_ex by auto
hoelzl@56328
   586
wenzelm@63540
   587
  obtain x where x: "a < x"
hoelzl@56328
   588
    using gt_ex by auto
wenzelm@63540
   589
  also from x have "x \<le> Max {a <..}"
hoelzl@56328
   590
    by fact
wenzelm@60758
   591
  also note \<open>Max {a <..} < y\<close>
hoelzl@56328
   592
  finally have "y \<le> Max { a <..}"
hoelzl@56328
   593
    by fact
wenzelm@60758
   594
  with \<open>Max {a <..} < y\<close> show False by auto
hoelzl@56328
   595
qed
hoelzl@56328
   596
hoelzl@56328
   597
lemma infinite_Ici: "\<not> finite {a :: 'a :: {no_top, linorder} ..}"
hoelzl@56328
   598
  using infinite_Ioi[of a] finite_subset[of "{a <..}" "{a ..}"]
hoelzl@56328
   599
  by (auto simp: subset_eq less_imp_le)
hoelzl@56328
   600
wenzelm@60758
   601
subsubsection \<open>Intersection\<close>
nipkow@32456
   602
nipkow@32456
   603
context linorder
nipkow@32456
   604
begin
nipkow@32456
   605
nipkow@32456
   606
lemma Int_atLeastAtMost[simp]: "{a..b} Int {c..d} = {max a c .. min b d}"
nipkow@32456
   607
by auto
nipkow@32456
   608
nipkow@32456
   609
lemma Int_atLeastAtMostR1[simp]: "{..b} Int {c..d} = {c .. min b d}"
nipkow@32456
   610
by auto
nipkow@32456
   611
nipkow@32456
   612
lemma Int_atLeastAtMostR2[simp]: "{a..} Int {c..d} = {max a c .. d}"
nipkow@32456
   613
by auto
nipkow@32456
   614
nipkow@32456
   615
lemma Int_atLeastAtMostL1[simp]: "{a..b} Int {..d} = {a .. min b d}"
nipkow@32456
   616
by auto
nipkow@32456
   617
nipkow@32456
   618
lemma Int_atLeastAtMostL2[simp]: "{a..b} Int {c..} = {max a c .. b}"
nipkow@32456
   619
by auto
nipkow@32456
   620
nipkow@32456
   621
lemma Int_atLeastLessThan[simp]: "{a..<b} Int {c..<d} = {max a c ..< min b d}"
nipkow@32456
   622
by auto
nipkow@32456
   623
nipkow@32456
   624
lemma Int_greaterThanAtMost[simp]: "{a<..b} Int {c<..d} = {max a c <.. min b d}"
nipkow@32456
   625
by auto
nipkow@32456
   626
nipkow@32456
   627
lemma Int_greaterThanLessThan[simp]: "{a<..<b} Int {c<..<d} = {max a c <..< min b d}"
nipkow@32456
   628
by auto
nipkow@32456
   629
hoelzl@50417
   630
lemma Int_atMost[simp]: "{..a} \<inter> {..b} = {.. min a b}"
hoelzl@50417
   631
  by (auto simp: min_def)
hoelzl@50417
   632
hoelzl@57447
   633
lemma Ioc_disjoint: "{a<..b} \<inter> {c<..d} = {} \<longleftrightarrow> b \<le> a \<or> d \<le> c \<or> b \<le> c \<or> d \<le> a"
wenzelm@63092
   634
  by auto
hoelzl@57447
   635
nipkow@32456
   636
end
nipkow@32456
   637
hoelzl@51329
   638
context complete_lattice
hoelzl@51329
   639
begin
hoelzl@51329
   640
hoelzl@51329
   641
lemma
hoelzl@51329
   642
  shows Sup_atLeast[simp]: "Sup {x ..} = top"
hoelzl@51329
   643
    and Sup_greaterThanAtLeast[simp]: "x < top \<Longrightarrow> Sup {x <..} = top"
hoelzl@51329
   644
    and Sup_atMost[simp]: "Sup {.. y} = y"
hoelzl@51329
   645
    and Sup_atLeastAtMost[simp]: "x \<le> y \<Longrightarrow> Sup { x .. y} = y"
hoelzl@51329
   646
    and Sup_greaterThanAtMost[simp]: "x < y \<Longrightarrow> Sup { x <.. y} = y"
hoelzl@51329
   647
  by (auto intro!: Sup_eqI)
hoelzl@51329
   648
hoelzl@51329
   649
lemma
hoelzl@51329
   650
  shows Inf_atMost[simp]: "Inf {.. x} = bot"
hoelzl@51329
   651
    and Inf_atMostLessThan[simp]: "top < x \<Longrightarrow> Inf {..< x} = bot"
hoelzl@51329
   652
    and Inf_atLeast[simp]: "Inf {x ..} = x"
hoelzl@51329
   653
    and Inf_atLeastAtMost[simp]: "x \<le> y \<Longrightarrow> Inf { x .. y} = x"
hoelzl@51329
   654
    and Inf_atLeastLessThan[simp]: "x < y \<Longrightarrow> Inf { x ..< y} = x"
hoelzl@51329
   655
  by (auto intro!: Inf_eqI)
hoelzl@51329
   656
hoelzl@51329
   657
end
hoelzl@51329
   658
hoelzl@51329
   659
lemma
hoelzl@53216
   660
  fixes x y :: "'a :: {complete_lattice, dense_linorder}"
hoelzl@51329
   661
  shows Sup_lessThan[simp]: "Sup {..< y} = y"
hoelzl@51329
   662
    and Sup_atLeastLessThan[simp]: "x < y \<Longrightarrow> Sup { x ..< y} = y"
hoelzl@51329
   663
    and Sup_greaterThanLessThan[simp]: "x < y \<Longrightarrow> Sup { x <..< y} = y"
hoelzl@51329
   664
    and Inf_greaterThan[simp]: "Inf {x <..} = x"
hoelzl@51329
   665
    and Inf_greaterThanAtMost[simp]: "x < y \<Longrightarrow> Inf { x <.. y} = x"
hoelzl@51329
   666
    and Inf_greaterThanLessThan[simp]: "x < y \<Longrightarrow> Inf { x <..< y} = x"
hoelzl@51329
   667
  by (auto intro!: Inf_eqI Sup_eqI intro: dense_le dense_le_bounded dense_ge dense_ge_bounded)
nipkow@32456
   668
wenzelm@60758
   669
subsection \<open>Intervals of natural numbers\<close>
paulson@14485
   670
wenzelm@60758
   671
subsubsection \<open>The Constant @{term lessThan}\<close>
paulson@15047
   672
paulson@14485
   673
lemma lessThan_0 [simp]: "lessThan (0::nat) = {}"
paulson@14485
   674
by (simp add: lessThan_def)
paulson@14485
   675
paulson@14485
   676
lemma lessThan_Suc: "lessThan (Suc k) = insert k (lessThan k)"
paulson@14485
   677
by (simp add: lessThan_def less_Suc_eq, blast)
paulson@14485
   678
wenzelm@60758
   679
text \<open>The following proof is convenient in induction proofs where
hoelzl@39072
   680
new elements get indices at the beginning. So it is used to transform
wenzelm@60758
   681
@{term "{..<Suc n}"} to @{term "0::nat"} and @{term "{..< n}"}.\<close>
hoelzl@39072
   682
hoelzl@59000
   683
lemma zero_notin_Suc_image: "0 \<notin> Suc ` A"
hoelzl@59000
   684
  by auto
hoelzl@59000
   685
hoelzl@39072
   686
lemma lessThan_Suc_eq_insert_0: "{..<Suc n} = insert 0 (Suc ` {..<n})"
hoelzl@59000
   687
  by (auto simp: image_iff less_Suc_eq_0_disj)
hoelzl@39072
   688
paulson@14485
   689
lemma lessThan_Suc_atMost: "lessThan (Suc k) = atMost k"
paulson@14485
   690
by (simp add: lessThan_def atMost_def less_Suc_eq_le)
paulson@14485
   691
hoelzl@59000
   692
lemma Iic_Suc_eq_insert_0: "{.. Suc n} = insert 0 (Suc ` {.. n})"
hoelzl@59000
   693
  unfolding lessThan_Suc_atMost[symmetric] lessThan_Suc_eq_insert_0[of "Suc n"] ..
hoelzl@59000
   694
paulson@14485
   695
lemma UN_lessThan_UNIV: "(UN m::nat. lessThan m) = UNIV"
paulson@14485
   696
by blast
paulson@14485
   697
wenzelm@60758
   698
subsubsection \<open>The Constant @{term greaterThan}\<close>
paulson@15047
   699
paulson@14485
   700
lemma greaterThan_0 [simp]: "greaterThan 0 = range Suc"
paulson@14485
   701
apply (simp add: greaterThan_def)
paulson@14485
   702
apply (blast dest: gr0_conv_Suc [THEN iffD1])
paulson@14485
   703
done
paulson@14485
   704
paulson@14485
   705
lemma greaterThan_Suc: "greaterThan (Suc k) = greaterThan k - {Suc k}"
paulson@14485
   706
apply (simp add: greaterThan_def)
paulson@14485
   707
apply (auto elim: linorder_neqE)
paulson@14485
   708
done
paulson@14485
   709
paulson@14485
   710
lemma INT_greaterThan_UNIV: "(INT m::nat. greaterThan m) = {}"
paulson@14485
   711
by blast
paulson@14485
   712
wenzelm@60758
   713
subsubsection \<open>The Constant @{term atLeast}\<close>
paulson@15047
   714
paulson@14485
   715
lemma atLeast_0 [simp]: "atLeast (0::nat) = UNIV"
paulson@14485
   716
by (unfold atLeast_def UNIV_def, simp)
paulson@14485
   717
paulson@14485
   718
lemma atLeast_Suc: "atLeast (Suc k) = atLeast k - {k}"
paulson@14485
   719
apply (simp add: atLeast_def)
paulson@14485
   720
apply (simp add: Suc_le_eq)
paulson@14485
   721
apply (simp add: order_le_less, blast)
paulson@14485
   722
done
paulson@14485
   723
paulson@14485
   724
lemma atLeast_Suc_greaterThan: "atLeast (Suc k) = greaterThan k"
paulson@14485
   725
  by (auto simp add: greaterThan_def atLeast_def less_Suc_eq_le)
paulson@14485
   726
paulson@14485
   727
lemma UN_atLeast_UNIV: "(UN m::nat. atLeast m) = UNIV"
paulson@14485
   728
by blast
paulson@14485
   729
wenzelm@60758
   730
subsubsection \<open>The Constant @{term atMost}\<close>
paulson@15047
   731
paulson@14485
   732
lemma atMost_0 [simp]: "atMost (0::nat) = {0}"
paulson@14485
   733
by (simp add: atMost_def)
paulson@14485
   734
paulson@14485
   735
lemma atMost_Suc: "atMost (Suc k) = insert (Suc k) (atMost k)"
paulson@14485
   736
apply (simp add: atMost_def)
paulson@14485
   737
apply (simp add: less_Suc_eq order_le_less, blast)
paulson@14485
   738
done
paulson@14485
   739
paulson@14485
   740
lemma UN_atMost_UNIV: "(UN m::nat. atMost m) = UNIV"
paulson@14485
   741
by blast
paulson@14485
   742
wenzelm@60758
   743
subsubsection \<open>The Constant @{term atLeastLessThan}\<close>
paulson@15047
   744
wenzelm@60758
   745
text\<open>The orientation of the following 2 rules is tricky. The lhs is
nipkow@24449
   746
defined in terms of the rhs.  Hence the chosen orientation makes sense
nipkow@24449
   747
in this theory --- the reverse orientation complicates proofs (eg
nipkow@24449
   748
nontermination). But outside, when the definition of the lhs is rarely
nipkow@24449
   749
used, the opposite orientation seems preferable because it reduces a
wenzelm@60758
   750
specific concept to a more general one.\<close>
nipkow@28068
   751
haftmann@63417
   752
lemma atLeast0LessThan [code_abbrev]: "{0::nat..<n} = {..<n}"
nipkow@15042
   753
by(simp add:lessThan_def atLeastLessThan_def)
nipkow@24449
   754
haftmann@63417
   755
lemma atLeast0AtMost [code_abbrev]: "{0..n::nat} = {..n}"
nipkow@28068
   756
by(simp add:atMost_def atLeastAtMost_def)
nipkow@28068
   757
haftmann@63417
   758
lemma lessThan_atLeast0:
haftmann@63417
   759
  "{..<n} = {0::nat..<n}"
haftmann@63417
   760
  by (simp add: atLeast0LessThan)
haftmann@63417
   761
haftmann@63417
   762
lemma atMost_atLeast0:
haftmann@63417
   763
  "{..n} = {0::nat..n}"
haftmann@63417
   764
  by (simp add: atLeast0AtMost)
nipkow@24449
   765
nipkow@24449
   766
lemma atLeastLessThan0: "{m..<0::nat} = {}"
paulson@15047
   767
by (simp add: atLeastLessThan_def)
nipkow@24449
   768
haftmann@63417
   769
lemma atLeast0_lessThan_Suc:
haftmann@63417
   770
  "{0..<Suc n} = insert n {0..<n}"
haftmann@63417
   771
  by (simp add: atLeast0LessThan lessThan_Suc)
haftmann@63417
   772
haftmann@63417
   773
lemma atLeast0_lessThan_Suc_eq_insert_0:
haftmann@63417
   774
  "{0..<Suc n} = insert 0 (Suc ` {0..<n})"
haftmann@63417
   775
  by (simp add: atLeast0LessThan lessThan_Suc_eq_insert_0)
haftmann@63417
   776
haftmann@63417
   777
haftmann@63417
   778
subsubsection \<open>The Constant @{term atLeastAtMost}\<close>
haftmann@63417
   779
haftmann@63417
   780
lemma atLeast0_atMost_Suc:
haftmann@63417
   781
  "{0..Suc n} = insert (Suc n) {0..n}"
haftmann@63417
   782
  by (simp add: atLeast0AtMost atMost_Suc)
haftmann@63417
   783
haftmann@63417
   784
lemma atLeast0_atMost_Suc_eq_insert_0:
haftmann@63417
   785
  "{0..Suc n} = insert 0 (Suc ` {0..n})"
haftmann@63417
   786
  by (simp add: atLeast0AtMost Iic_Suc_eq_insert_0)
haftmann@63417
   787
haftmann@63417
   788
wenzelm@60758
   789
subsubsection \<open>Intervals of nats with @{term Suc}\<close>
paulson@15047
   790
wenzelm@60758
   791
text\<open>Not a simprule because the RHS is too messy.\<close>
paulson@15047
   792
lemma atLeastLessThanSuc:
paulson@15047
   793
    "{m..<Suc n} = (if m \<le> n then insert n {m..<n} else {})"
paulson@15418
   794
by (auto simp add: atLeastLessThan_def)
paulson@15047
   795
paulson@15418
   796
lemma atLeastLessThan_singleton [simp]: "{m..<Suc m} = {m}"
paulson@15047
   797
by (auto simp add: atLeastLessThan_def)
nipkow@16041
   798
(*
paulson@15047
   799
lemma atLeast_sum_LessThan [simp]: "{m + k..<k::nat} = {}"
paulson@15047
   800
by (induct k, simp_all add: atLeastLessThanSuc)
paulson@15047
   801
paulson@15047
   802
lemma atLeastSucLessThan [simp]: "{Suc n..<n} = {}"
paulson@15047
   803
by (auto simp add: atLeastLessThan_def)
nipkow@16041
   804
*)
nipkow@15045
   805
lemma atLeastLessThanSuc_atLeastAtMost: "{l..<Suc u} = {l..u}"
paulson@14485
   806
  by (simp add: lessThan_Suc_atMost atLeastAtMost_def atLeastLessThan_def)
paulson@14485
   807
paulson@15418
   808
lemma atLeastSucAtMost_greaterThanAtMost: "{Suc l..u} = {l<..u}"
paulson@15418
   809
  by (simp add: atLeast_Suc_greaterThan atLeastAtMost_def
paulson@14485
   810
    greaterThanAtMost_def)
paulson@14485
   811
paulson@15418
   812
lemma atLeastSucLessThan_greaterThanLessThan: "{Suc l..<u} = {l<..<u}"
paulson@15418
   813
  by (simp add: atLeast_Suc_greaterThan atLeastLessThan_def
paulson@14485
   814
    greaterThanLessThan_def)
paulson@14485
   815
nipkow@15554
   816
lemma atLeastAtMostSuc_conv: "m \<le> Suc n \<Longrightarrow> {m..Suc n} = insert (Suc n) {m..n}"
nipkow@15554
   817
by (auto simp add: atLeastAtMost_def)
nipkow@15554
   818
noschinl@45932
   819
lemma atLeastAtMost_insertL: "m \<le> n \<Longrightarrow> insert m {Suc m..n} = {m ..n}"
noschinl@45932
   820
by auto
noschinl@45932
   821
wenzelm@60758
   822
text \<open>The analogous result is useful on @{typ int}:\<close>
kleing@43157
   823
(* here, because we don't have an own int section *)
kleing@43157
   824
lemma atLeastAtMostPlus1_int_conv:
kleing@43157
   825
  "m <= 1+n \<Longrightarrow> {m..1+n} = insert (1+n) {m..n::int}"
kleing@43157
   826
  by (auto intro: set_eqI)
kleing@43157
   827
paulson@33044
   828
lemma atLeastLessThan_add_Un: "i \<le> j \<Longrightarrow> {i..<j+k} = {i..<j} \<union> {j..<j+k::nat}"
hoelzl@62369
   829
  apply (induct k)
hoelzl@62369
   830
  apply (simp_all add: atLeastLessThanSuc)
paulson@33044
   831
  done
paulson@33044
   832
wenzelm@60758
   833
subsubsection \<open>Intervals and numerals\<close>
lp15@57113
   834
wenzelm@61799
   835
lemma lessThan_nat_numeral:  \<comment>\<open>Evaluation for specific numerals\<close>
lp15@57113
   836
  "lessThan (numeral k :: nat) = insert (pred_numeral k) (lessThan (pred_numeral k))"
lp15@57113
   837
  by (simp add: numeral_eq_Suc lessThan_Suc)
lp15@57113
   838
wenzelm@61799
   839
lemma atMost_nat_numeral:  \<comment>\<open>Evaluation for specific numerals\<close>
lp15@57113
   840
  "atMost (numeral k :: nat) = insert (numeral k) (atMost (pred_numeral k))"
lp15@57113
   841
  by (simp add: numeral_eq_Suc atMost_Suc)
lp15@57113
   842
wenzelm@61799
   843
lemma atLeastLessThan_nat_numeral:  \<comment>\<open>Evaluation for specific numerals\<close>
hoelzl@62369
   844
  "atLeastLessThan m (numeral k :: nat) =
lp15@57113
   845
     (if m \<le> (pred_numeral k) then insert (pred_numeral k) (atLeastLessThan m (pred_numeral k))
lp15@57113
   846
                 else {})"
lp15@57113
   847
  by (simp add: numeral_eq_Suc atLeastLessThanSuc)
lp15@57113
   848
wenzelm@60758
   849
subsubsection \<open>Image\<close>
nipkow@16733
   850
lp15@60809
   851
lemma image_add_atLeastAtMost [simp]:
lp15@60615
   852
  fixes k ::"'a::linordered_semidom"
lp15@60615
   853
  shows "(\<lambda>n. n+k) ` {i..j} = {i+k..j+k}" (is "?A = ?B")
nipkow@16733
   854
proof
nipkow@16733
   855
  show "?A \<subseteq> ?B" by auto
nipkow@16733
   856
next
nipkow@16733
   857
  show "?B \<subseteq> ?A"
nipkow@16733
   858
  proof
nipkow@16733
   859
    fix n assume a: "n : ?B"
lp15@60615
   860
    hence "n - k : {i..j}"
lp15@60615
   861
      by (auto simp: add_le_imp_le_diff add_le_add_imp_diff_le)
lp15@60615
   862
    moreover have "n = (n - k) + k" using a
lp15@60615
   863
    proof -
lp15@60615
   864
      have "k + i \<le> n"
lp15@60615
   865
        by (metis a add.commute atLeastAtMost_iff)
lp15@60615
   866
      hence "k + (n - k) = n"
lp15@60615
   867
        by (metis (no_types) ab_semigroup_add_class.add_ac(1) add_diff_cancel_left' le_add_diff_inverse)
lp15@60615
   868
      thus ?thesis
lp15@60615
   869
        by (simp add: add.commute)
lp15@60615
   870
    qed
nipkow@16733
   871
    ultimately show "n : ?A" by blast
nipkow@16733
   872
  qed
nipkow@16733
   873
qed
nipkow@16733
   874
lp15@60809
   875
lemma image_diff_atLeastAtMost [simp]:
lp15@60809
   876
  fixes d::"'a::linordered_idom" shows "(op - d ` {a..b}) = {d-b..d-a}"
lp15@60809
   877
  apply auto
lp15@60809
   878
  apply (rule_tac x="d-x" in rev_image_eqI, auto)
lp15@60809
   879
  done
lp15@60809
   880
lp15@60809
   881
lemma image_mult_atLeastAtMost [simp]:
lp15@60809
   882
  fixes d::"'a::linordered_field"
lp15@60809
   883
  assumes "d>0" shows "(op * d ` {a..b}) = {d*a..d*b}"
lp15@60809
   884
  using assms
lp15@60809
   885
  by (auto simp: field_simps mult_le_cancel_right intro: rev_image_eqI [where x="x/d" for x])
lp15@60809
   886
lp15@60809
   887
lemma image_affinity_atLeastAtMost:
lp15@60809
   888
  fixes c :: "'a::linordered_field"
lp15@60809
   889
  shows "((\<lambda>x. m*x + c) ` {a..b}) = (if {a..b}={} then {}
lp15@60809
   890
            else if 0 \<le> m then {m*a + c .. m *b + c}
lp15@60809
   891
            else {m*b + c .. m*a + c})"
lp15@60809
   892
  apply (case_tac "m=0", auto simp: mult_le_cancel_left)
lp15@60809
   893
  apply (rule_tac x="inverse m*(x-c)" in rev_image_eqI, auto simp: field_simps)
lp15@60809
   894
  apply (rule_tac x="inverse m*(x-c)" in rev_image_eqI, auto simp: field_simps)
lp15@60809
   895
  done
lp15@60809
   896
lp15@60809
   897
lemma image_affinity_atLeastAtMost_diff:
lp15@60809
   898
  fixes c :: "'a::linordered_field"
lp15@60809
   899
  shows "((\<lambda>x. m*x - c) ` {a..b}) = (if {a..b}={} then {}
lp15@60809
   900
            else if 0 \<le> m then {m*a - c .. m*b - c}
lp15@60809
   901
            else {m*b - c .. m*a - c})"
lp15@60809
   902
  using image_affinity_atLeastAtMost [of m "-c" a b]
lp15@60809
   903
  by simp
lp15@60809
   904
paulson@61204
   905
lemma image_affinity_atLeastAtMost_div:
paulson@61204
   906
  fixes c :: "'a::linordered_field"
paulson@61204
   907
  shows "((\<lambda>x. x/m + c) ` {a..b}) = (if {a..b}={} then {}
paulson@61204
   908
            else if 0 \<le> m then {a/m + c .. b/m + c}
paulson@61204
   909
            else {b/m + c .. a/m + c})"
paulson@61204
   910
  using image_affinity_atLeastAtMost [of "inverse m" c a b]
paulson@61204
   911
  by (simp add: field_class.field_divide_inverse algebra_simps)
hoelzl@62369
   912
lp15@60809
   913
lemma image_affinity_atLeastAtMost_div_diff:
lp15@60809
   914
  fixes c :: "'a::linordered_field"
lp15@60809
   915
  shows "((\<lambda>x. x/m - c) ` {a..b}) = (if {a..b}={} then {}
lp15@60809
   916
            else if 0 \<le> m then {a/m - c .. b/m - c}
lp15@60809
   917
            else {b/m - c .. a/m - c})"
lp15@60809
   918
  using image_affinity_atLeastAtMost_diff [of "inverse m" c a b]
lp15@60809
   919
  by (simp add: field_class.field_divide_inverse algebra_simps)
lp15@60809
   920
nipkow@16733
   921
lemma image_add_atLeastLessThan:
nipkow@16733
   922
  "(%n::nat. n+k) ` {i..<j} = {i+k..<j+k}" (is "?A = ?B")
nipkow@16733
   923
proof
nipkow@16733
   924
  show "?A \<subseteq> ?B" by auto
nipkow@16733
   925
next
nipkow@16733
   926
  show "?B \<subseteq> ?A"
nipkow@16733
   927
  proof
nipkow@16733
   928
    fix n assume a: "n : ?B"
webertj@20217
   929
    hence "n - k : {i..<j}" by auto
nipkow@16733
   930
    moreover have "n = (n - k) + k" using a by auto
nipkow@16733
   931
    ultimately show "n : ?A" by blast
nipkow@16733
   932
  qed
nipkow@16733
   933
qed
nipkow@16733
   934
haftmann@63365
   935
corollary image_Suc_lessThan:
haftmann@63365
   936
  "Suc ` {..<n} = {1..n}"
haftmann@63365
   937
  using image_add_atLeastLessThan [of 1 0 n]
haftmann@63365
   938
  by (auto simp add: lessThan_Suc_atMost atLeast0LessThan)
wenzelm@63915
   939
haftmann@63365
   940
corollary image_Suc_atMost:
haftmann@63365
   941
  "Suc ` {..n} = {1..Suc n}"
haftmann@63365
   942
  using image_add_atLeastLessThan [of 1 0 "Suc n"]
haftmann@63365
   943
  by (auto simp add: lessThan_Suc_atMost atLeast0LessThan)
haftmann@63365
   944
nipkow@16733
   945
corollary image_Suc_atLeastAtMost[simp]:
nipkow@16733
   946
  "Suc ` {i..j} = {Suc i..Suc j}"
huffman@30079
   947
using image_add_atLeastAtMost[where k="Suc 0"] by simp
nipkow@16733
   948
nipkow@16733
   949
corollary image_Suc_atLeastLessThan[simp]:
nipkow@16733
   950
  "Suc ` {i..<j} = {Suc i..<Suc j}"
huffman@30079
   951
using image_add_atLeastLessThan[where k="Suc 0"] by simp
nipkow@16733
   952
haftmann@63365
   953
lemma atLeast1_lessThan_eq_remove0:
haftmann@63365
   954
  "{Suc 0..<n} = {..<n} - {0}"
haftmann@63365
   955
  by auto
haftmann@63365
   956
haftmann@63365
   957
lemma atLeast1_atMost_eq_remove0:
haftmann@63365
   958
  "{Suc 0..n} = {..n} - {0}"
haftmann@63365
   959
  by auto
haftmann@63365
   960
nipkow@16733
   961
lemma image_add_int_atLeastLessThan:
nipkow@16733
   962
    "(%x. x + (l::int)) ` {0..<u-l} = {l..<u}"
nipkow@16733
   963
  apply (auto simp add: image_def)
nipkow@16733
   964
  apply (rule_tac x = "x - l" in bexI)
nipkow@16733
   965
  apply auto
nipkow@16733
   966
  done
nipkow@16733
   967
hoelzl@37664
   968
lemma image_minus_const_atLeastLessThan_nat:
hoelzl@37664
   969
  fixes c :: nat
hoelzl@37664
   970
  shows "(\<lambda>i. i - c) ` {x ..< y} =
hoelzl@37664
   971
      (if c < y then {x - c ..< y - c} else if x < y then {0} else {})"
hoelzl@37664
   972
    (is "_ = ?right")
hoelzl@37664
   973
proof safe
hoelzl@37664
   974
  fix a assume a: "a \<in> ?right"
hoelzl@37664
   975
  show "a \<in> (\<lambda>i. i - c) ` {x ..< y}"
hoelzl@37664
   976
  proof cases
hoelzl@37664
   977
    assume "c < y" with a show ?thesis
hoelzl@37664
   978
      by (auto intro!: image_eqI[of _ _ "a + c"])
hoelzl@37664
   979
  next
hoelzl@37664
   980
    assume "\<not> c < y" with a show ?thesis
nipkow@62390
   981
      by (auto intro!: image_eqI[of _ _ x] split: if_split_asm)
hoelzl@37664
   982
  qed
hoelzl@37664
   983
qed auto
hoelzl@37664
   984
Andreas@51152
   985
lemma image_int_atLeastLessThan: "int ` {a..<b} = {int a..<int b}"
wenzelm@55143
   986
  by (auto intro!: image_eqI [where x = "nat x" for x])
Andreas@51152
   987
hoelzl@35580
   988
context ordered_ab_group_add
hoelzl@35580
   989
begin
hoelzl@35580
   990
hoelzl@35580
   991
lemma
hoelzl@35580
   992
  fixes x :: 'a
hoelzl@35580
   993
  shows image_uminus_greaterThan[simp]: "uminus ` {x<..} = {..<-x}"
hoelzl@35580
   994
  and image_uminus_atLeast[simp]: "uminus ` {x..} = {..-x}"
hoelzl@35580
   995
proof safe
hoelzl@35580
   996
  fix y assume "y < -x"
hoelzl@35580
   997
  hence *:  "x < -y" using neg_less_iff_less[of "-y" x] by simp
hoelzl@35580
   998
  have "- (-y) \<in> uminus ` {x<..}"
hoelzl@35580
   999
    by (rule imageI) (simp add: *)
hoelzl@35580
  1000
  thus "y \<in> uminus ` {x<..}" by simp
hoelzl@35580
  1001
next
hoelzl@35580
  1002
  fix y assume "y \<le> -x"
hoelzl@35580
  1003
  have "- (-y) \<in> uminus ` {x..}"
wenzelm@60758
  1004
    by (rule imageI) (insert \<open>y \<le> -x\<close>[THEN le_imp_neg_le], simp)
hoelzl@35580
  1005
  thus "y \<in> uminus ` {x..}" by simp
hoelzl@35580
  1006
qed simp_all
hoelzl@35580
  1007
hoelzl@35580
  1008
lemma
hoelzl@35580
  1009
  fixes x :: 'a
hoelzl@35580
  1010
  shows image_uminus_lessThan[simp]: "uminus ` {..<x} = {-x<..}"
hoelzl@35580
  1011
  and image_uminus_atMost[simp]: "uminus ` {..x} = {-x..}"
hoelzl@35580
  1012
proof -
hoelzl@35580
  1013
  have "uminus ` {..<x} = uminus ` uminus ` {-x<..}"
hoelzl@35580
  1014
    and "uminus ` {..x} = uminus ` uminus ` {-x..}" by simp_all
hoelzl@35580
  1015
  thus "uminus ` {..<x} = {-x<..}" and "uminus ` {..x} = {-x..}"
hoelzl@35580
  1016
    by (simp_all add: image_image
hoelzl@35580
  1017
        del: image_uminus_greaterThan image_uminus_atLeast)
hoelzl@35580
  1018
qed
hoelzl@35580
  1019
hoelzl@35580
  1020
lemma
hoelzl@35580
  1021
  fixes x :: 'a
hoelzl@35580
  1022
  shows image_uminus_atLeastAtMost[simp]: "uminus ` {x..y} = {-y..-x}"
hoelzl@35580
  1023
  and image_uminus_greaterThanAtMost[simp]: "uminus ` {x<..y} = {-y..<-x}"
hoelzl@35580
  1024
  and image_uminus_atLeastLessThan[simp]: "uminus ` {x..<y} = {-y<..-x}"
hoelzl@35580
  1025
  and image_uminus_greaterThanLessThan[simp]: "uminus ` {x<..<y} = {-y<..<-x}"
hoelzl@35580
  1026
  by (simp_all add: atLeastAtMost_def greaterThanAtMost_def atLeastLessThan_def
hoelzl@35580
  1027
      greaterThanLessThan_def image_Int[OF inj_uminus] Int_commute)
hoelzl@35580
  1028
end
nipkow@16733
  1029
wenzelm@60758
  1030
subsubsection \<open>Finiteness\<close>
paulson@14485
  1031
nipkow@15045
  1032
lemma finite_lessThan [iff]: fixes k :: nat shows "finite {..<k}"
paulson@14485
  1033
  by (induct k) (simp_all add: lessThan_Suc)
paulson@14485
  1034
paulson@14485
  1035
lemma finite_atMost [iff]: fixes k :: nat shows "finite {..k}"
paulson@14485
  1036
  by (induct k) (simp_all add: atMost_Suc)
paulson@14485
  1037
paulson@14485
  1038
lemma finite_greaterThanLessThan [iff]:
nipkow@15045
  1039
  fixes l :: nat shows "finite {l<..<u}"
paulson@14485
  1040
by (simp add: greaterThanLessThan_def)
paulson@14485
  1041
paulson@14485
  1042
lemma finite_atLeastLessThan [iff]:
nipkow@15045
  1043
  fixes l :: nat shows "finite {l..<u}"
paulson@14485
  1044
by (simp add: atLeastLessThan_def)
paulson@14485
  1045
paulson@14485
  1046
lemma finite_greaterThanAtMost [iff]:
nipkow@15045
  1047
  fixes l :: nat shows "finite {l<..u}"
paulson@14485
  1048
by (simp add: greaterThanAtMost_def)
paulson@14485
  1049
paulson@14485
  1050
lemma finite_atLeastAtMost [iff]:
paulson@14485
  1051
  fixes l :: nat shows "finite {l..u}"
paulson@14485
  1052
by (simp add: atLeastAtMost_def)
paulson@14485
  1053
wenzelm@60758
  1054
text \<open>A bounded set of natural numbers is finite.\<close>
paulson@14485
  1055
lemma bounded_nat_set_is_finite:
nipkow@24853
  1056
  "(ALL i:N. i < (n::nat)) ==> finite N"
nipkow@28068
  1057
apply (rule finite_subset)
nipkow@28068
  1058
 apply (rule_tac [2] finite_lessThan, auto)
nipkow@28068
  1059
done
nipkow@28068
  1060
wenzelm@60758
  1061
text \<open>A set of natural numbers is finite iff it is bounded.\<close>
nipkow@31044
  1062
lemma finite_nat_set_iff_bounded:
nipkow@31044
  1063
  "finite(N::nat set) = (EX m. ALL n:N. n<m)" (is "?F = ?B")
nipkow@31044
  1064
proof
nipkow@31044
  1065
  assume f:?F  show ?B
wenzelm@60758
  1066
    using Max_ge[OF \<open>?F\<close>, simplified less_Suc_eq_le[symmetric]] by blast
nipkow@31044
  1067
next
wenzelm@60758
  1068
  assume ?B show ?F using \<open>?B\<close> by(blast intro:bounded_nat_set_is_finite)
nipkow@31044
  1069
qed
nipkow@31044
  1070
nipkow@31044
  1071
lemma finite_nat_set_iff_bounded_le:
nipkow@31044
  1072
  "finite(N::nat set) = (EX m. ALL n:N. n<=m)"
nipkow@31044
  1073
apply(simp add:finite_nat_set_iff_bounded)
nipkow@31044
  1074
apply(blast dest:less_imp_le_nat le_imp_less_Suc)
nipkow@31044
  1075
done
nipkow@31044
  1076
nipkow@28068
  1077
lemma finite_less_ub:
nipkow@28068
  1078
     "!!f::nat=>nat. (!!n. n \<le> f n) ==> finite {n. f n \<le> u}"
nipkow@28068
  1079
by (rule_tac B="{..u}" in finite_subset, auto intro: order_trans)
paulson@14485
  1080
hoelzl@56328
  1081
wenzelm@60758
  1082
text\<open>Any subset of an interval of natural numbers the size of the
wenzelm@60758
  1083
subset is exactly that interval.\<close>
nipkow@24853
  1084
nipkow@24853
  1085
lemma subset_card_intvl_is_intvl:
blanchet@55085
  1086
  assumes "A \<subseteq> {k..<k + card A}"
blanchet@55085
  1087
  shows "A = {k..<k + card A}"
wenzelm@53374
  1088
proof (cases "finite A")
wenzelm@53374
  1089
  case True
wenzelm@53374
  1090
  from this and assms show ?thesis
wenzelm@53374
  1091
  proof (induct A rule: finite_linorder_max_induct)
nipkow@24853
  1092
    case empty thus ?case by auto
nipkow@24853
  1093
  next
nipkow@33434
  1094
    case (insert b A)
wenzelm@53374
  1095
    hence *: "b \<notin> A" by auto
blanchet@55085
  1096
    with insert have "A <= {k..<k + card A}" and "b = k + card A"
wenzelm@53374
  1097
      by fastforce+
wenzelm@53374
  1098
    with insert * show ?case by auto
nipkow@24853
  1099
  qed
nipkow@24853
  1100
next
wenzelm@53374
  1101
  case False
wenzelm@53374
  1102
  with assms show ?thesis by simp
nipkow@24853
  1103
qed
nipkow@24853
  1104
nipkow@24853
  1105
wenzelm@60758
  1106
subsubsection \<open>Proving Inclusions and Equalities between Unions\<close>
paulson@32596
  1107
nipkow@36755
  1108
lemma UN_le_eq_Un0:
nipkow@36755
  1109
  "(\<Union>i\<le>n::nat. M i) = (\<Union>i\<in>{1..n}. M i) \<union> M 0" (is "?A = ?B")
nipkow@36755
  1110
proof
nipkow@36755
  1111
  show "?A <= ?B"
nipkow@36755
  1112
  proof
nipkow@36755
  1113
    fix x assume "x : ?A"
nipkow@36755
  1114
    then obtain i where i: "i\<le>n" "x : M i" by auto
nipkow@36755
  1115
    show "x : ?B"
nipkow@36755
  1116
    proof(cases i)
nipkow@36755
  1117
      case 0 with i show ?thesis by simp
nipkow@36755
  1118
    next
nipkow@36755
  1119
      case (Suc j) with i show ?thesis by auto
nipkow@36755
  1120
    qed
nipkow@36755
  1121
  qed
nipkow@36755
  1122
next
wenzelm@63171
  1123
  show "?B <= ?A" by fastforce
nipkow@36755
  1124
qed
nipkow@36755
  1125
nipkow@36755
  1126
lemma UN_le_add_shift:
nipkow@36755
  1127
  "(\<Union>i\<le>n::nat. M(i+k)) = (\<Union>i\<in>{k..n+k}. M i)" (is "?A = ?B")
nipkow@36755
  1128
proof
nipkow@44890
  1129
  show "?A <= ?B" by fastforce
nipkow@36755
  1130
next
nipkow@36755
  1131
  show "?B <= ?A"
nipkow@36755
  1132
  proof
nipkow@36755
  1133
    fix x assume "x : ?B"
nipkow@36755
  1134
    then obtain i where i: "i : {k..n+k}" "x : M(i)" by auto
nipkow@36755
  1135
    hence "i-k\<le>n & x : M((i-k)+k)" by auto
nipkow@36755
  1136
    thus "x : ?A" by blast
nipkow@36755
  1137
  qed
nipkow@36755
  1138
qed
nipkow@36755
  1139
hoelzl@62369
  1140
lemma UN_UN_finite_eq: "(\<Union>n::nat. \<Union>i\<in>{0..<n}. A i) = (\<Union>n. A n)"
hoelzl@62369
  1141
  by (auto simp add: atLeast0LessThan)
paulson@32596
  1142
haftmann@62343
  1143
lemma UN_finite_subset:
haftmann@62343
  1144
  "(\<And>n::nat. (\<Union>i\<in>{0..<n}. A i) \<subseteq> C) \<Longrightarrow> (\<Union>n. A n) \<subseteq> C"
paulson@32596
  1145
  by (subst UN_UN_finite_eq [symmetric]) blast
paulson@32596
  1146
hoelzl@62369
  1147
lemma UN_finite2_subset:
haftmann@62343
  1148
  assumes "\<And>n::nat. (\<Union>i\<in>{0..<n}. A i) \<subseteq> (\<Union>i\<in>{0..<n + k}. B i)"
haftmann@62343
  1149
  shows "(\<Union>n. A n) \<subseteq> (\<Union>n. B n)"
haftmann@62343
  1150
proof (rule UN_finite_subset, rule)
haftmann@62343
  1151
  fix n and a
haftmann@62343
  1152
  from assms have "(\<Union>i\<in>{0..<n}. A i) \<subseteq> (\<Union>i\<in>{0..<n + k}. B i)" .
haftmann@62343
  1153
  moreover assume "a \<in> (\<Union>i\<in>{0..<n}. A i)"
haftmann@62343
  1154
  ultimately have "a \<in> (\<Union>i\<in>{0..<n + k}. B i)" by blast
haftmann@62343
  1155
  then show "a \<in> (\<Union>i. B i)" by (auto simp add: UN_UN_finite_eq)
haftmann@62343
  1156
qed
paulson@32596
  1157
paulson@32596
  1158
lemma UN_finite2_eq:
haftmann@62343
  1159
  "(\<And>n::nat. (\<Union>i\<in>{0..<n}. A i) = (\<Union>i\<in>{0..<n + k}. B i)) \<Longrightarrow>
haftmann@62343
  1160
    (\<Union>n. A n) = (\<Union>n. B n)"
paulson@33044
  1161
  apply (rule subset_antisym)
paulson@33044
  1162
   apply (rule UN_finite2_subset, blast)
haftmann@62343
  1163
  apply (rule UN_finite2_subset [where k=k])
haftmann@62343
  1164
  apply (force simp add: atLeastLessThan_add_Un [of 0])
haftmann@62343
  1165
  done
paulson@32596
  1166
paulson@32596
  1167
wenzelm@60758
  1168
subsubsection \<open>Cardinality\<close>
paulson@14485
  1169
nipkow@15045
  1170
lemma card_lessThan [simp]: "card {..<u} = u"
paulson@15251
  1171
  by (induct u, simp_all add: lessThan_Suc)
paulson@14485
  1172
paulson@14485
  1173
lemma card_atMost [simp]: "card {..u} = Suc u"
paulson@14485
  1174
  by (simp add: lessThan_Suc_atMost [THEN sym])
paulson@14485
  1175
nipkow@15045
  1176
lemma card_atLeastLessThan [simp]: "card {l..<u} = u - l"
lp15@57113
  1177
proof -
lp15@57113
  1178
  have "{l..<u} = (%x. x + l) ` {..<u-l}"
lp15@57113
  1179
    apply (auto simp add: image_def atLeastLessThan_def lessThan_def)
lp15@57113
  1180
    apply (rule_tac x = "x - l" in exI)
lp15@57113
  1181
    apply arith
lp15@57113
  1182
    done
lp15@57113
  1183
  then have "card {l..<u} = card {..<u-l}"
lp15@57113
  1184
    by (simp add: card_image inj_on_def)
lp15@57113
  1185
  then show ?thesis
lp15@57113
  1186
    by simp
lp15@57113
  1187
qed
paulson@14485
  1188
paulson@15418
  1189
lemma card_atLeastAtMost [simp]: "card {l..u} = Suc u - l"
paulson@14485
  1190
  by (subst atLeastLessThanSuc_atLeastAtMost [THEN sym], simp)
paulson@14485
  1191
paulson@15418
  1192
lemma card_greaterThanAtMost [simp]: "card {l<..u} = u - l"
paulson@14485
  1193
  by (subst atLeastSucAtMost_greaterThanAtMost [THEN sym], simp)
paulson@14485
  1194
nipkow@15045
  1195
lemma card_greaterThanLessThan [simp]: "card {l<..<u} = u - Suc l"
paulson@14485
  1196
  by (subst atLeastSucLessThan_greaterThanLessThan [THEN sym], simp)
paulson@14485
  1197
haftmann@63417
  1198
lemma subset_eq_atLeast0_lessThan_finite:
haftmann@63365
  1199
  fixes n :: nat
haftmann@63417
  1200
  assumes "N \<subseteq> {0..<n}"
wenzelm@63915
  1201
  shows "finite N"
haftmann@63417
  1202
  using assms finite_atLeastLessThan by (rule finite_subset)
haftmann@63417
  1203
haftmann@63417
  1204
lemma subset_eq_atLeast0_atMost_finite:
haftmann@63417
  1205
  fixes n :: nat
haftmann@63417
  1206
  assumes "N \<subseteq> {0..n}"
wenzelm@63915
  1207
  shows "finite N"
haftmann@63417
  1208
  using assms finite_atLeastAtMost by (rule finite_subset)
haftmann@63365
  1209
nipkow@26105
  1210
lemma ex_bij_betw_nat_finite:
nipkow@26105
  1211
  "finite M \<Longrightarrow> \<exists>h. bij_betw h {0..<card M} M"
nipkow@26105
  1212
apply(drule finite_imp_nat_seg_image_inj_on)
nipkow@26105
  1213
apply(auto simp:atLeast0LessThan[symmetric] lessThan_def[symmetric] card_image bij_betw_def)
nipkow@26105
  1214
done
nipkow@26105
  1215
nipkow@26105
  1216
lemma ex_bij_betw_finite_nat:
nipkow@26105
  1217
  "finite M \<Longrightarrow> \<exists>h. bij_betw h M {0..<card M}"
nipkow@26105
  1218
by (blast dest: ex_bij_betw_nat_finite bij_betw_inv)
nipkow@26105
  1219
nipkow@31438
  1220
lemma finite_same_card_bij:
nipkow@31438
  1221
  "finite A \<Longrightarrow> finite B \<Longrightarrow> card A = card B \<Longrightarrow> EX h. bij_betw h A B"
nipkow@31438
  1222
apply(drule ex_bij_betw_finite_nat)
nipkow@31438
  1223
apply(drule ex_bij_betw_nat_finite)
nipkow@31438
  1224
apply(auto intro!:bij_betw_trans)
nipkow@31438
  1225
done
nipkow@31438
  1226
nipkow@31438
  1227
lemma ex_bij_betw_nat_finite_1:
nipkow@31438
  1228
  "finite M \<Longrightarrow> \<exists>h. bij_betw h {1 .. card M} M"
nipkow@31438
  1229
by (rule finite_same_card_bij) auto
nipkow@31438
  1230
hoelzl@40703
  1231
lemma bij_betw_iff_card:
lp15@63114
  1232
  assumes "finite A" "finite B"
lp15@63114
  1233
  shows "(\<exists>f. bij_betw f A B) \<longleftrightarrow> (card A = card B)"
lp15@63114
  1234
proof
lp15@63114
  1235
  assume "card A = card B"
lp15@63114
  1236
  moreover obtain f where "bij_betw f A {0 ..< card A}"
lp15@63114
  1237
    using assms ex_bij_betw_finite_nat by blast
hoelzl@40703
  1238
  moreover obtain g where "bij_betw g {0 ..< card B} B"
lp15@63114
  1239
    using assms ex_bij_betw_nat_finite by blast
hoelzl@40703
  1240
  ultimately have "bij_betw (g o f) A B"
lp15@63114
  1241
    by (auto simp: bij_betw_trans)
hoelzl@40703
  1242
  thus "(\<exists>f. bij_betw f A B)" by blast
lp15@63114
  1243
qed (auto simp: bij_betw_same_card)
hoelzl@40703
  1244
hoelzl@40703
  1245
lemma inj_on_iff_card_le:
hoelzl@40703
  1246
  assumes FIN: "finite A" and FIN': "finite B"
hoelzl@40703
  1247
  shows "(\<exists>f. inj_on f A \<and> f ` A \<le> B) = (card A \<le> card B)"
hoelzl@40703
  1248
proof (safe intro!: card_inj_on_le)
hoelzl@40703
  1249
  assume *: "card A \<le> card B"
hoelzl@40703
  1250
  obtain f where 1: "inj_on f A" and 2: "f ` A = {0 ..< card A}"
hoelzl@40703
  1251
  using FIN ex_bij_betw_finite_nat unfolding bij_betw_def by force
hoelzl@40703
  1252
  moreover obtain g where "inj_on g {0 ..< card B}" and 3: "g ` {0 ..< card B} = B"
hoelzl@40703
  1253
  using FIN' ex_bij_betw_nat_finite unfolding bij_betw_def by force
hoelzl@40703
  1254
  ultimately have "inj_on g (f ` A)" using subset_inj_on[of g _ "f ` A"] * by force
hoelzl@40703
  1255
  hence "inj_on (g o f) A" using 1 comp_inj_on by blast
hoelzl@40703
  1256
  moreover
hoelzl@40703
  1257
  {have "{0 ..< card A} \<le> {0 ..< card B}" using * by force
hoelzl@40703
  1258
   with 2 have "f ` A  \<le> {0 ..< card B}" by blast
hoelzl@40703
  1259
   hence "(g o f) ` A \<le> B" unfolding comp_def using 3 by force
hoelzl@40703
  1260
  }
hoelzl@40703
  1261
  ultimately show "(\<exists>f. inj_on f A \<and> f ` A \<le> B)" by blast
hoelzl@40703
  1262
qed (insert assms, auto)
nipkow@26105
  1263
haftmann@63417
  1264
lemma subset_eq_atLeast0_lessThan_card:
haftmann@63365
  1265
  fixes n :: nat
haftmann@63417
  1266
  assumes "N \<subseteq> {0..<n}"
haftmann@63365
  1267
  shows "card N \<le> n"
haftmann@63365
  1268
proof -
haftmann@63417
  1269
  from assms finite_lessThan have "card N \<le> card {0..<n}"
haftmann@63365
  1270
    using card_mono by blast
haftmann@63365
  1271
  then show ?thesis by simp
haftmann@63365
  1272
qed
haftmann@63365
  1273
haftmann@63365
  1274
wenzelm@60758
  1275
subsection \<open>Intervals of integers\<close>
paulson@14485
  1276
nipkow@15045
  1277
lemma atLeastLessThanPlusOne_atLeastAtMost_int: "{l..<u+1} = {l..(u::int)}"
paulson@14485
  1278
  by (auto simp add: atLeastAtMost_def atLeastLessThan_def)
paulson@14485
  1279
paulson@15418
  1280
lemma atLeastPlusOneAtMost_greaterThanAtMost_int: "{l+1..u} = {l<..(u::int)}"
paulson@14485
  1281
  by (auto simp add: atLeastAtMost_def greaterThanAtMost_def)
paulson@14485
  1282
paulson@15418
  1283
lemma atLeastPlusOneLessThan_greaterThanLessThan_int:
paulson@15418
  1284
    "{l+1..<u} = {l<..<u::int}"
paulson@14485
  1285
  by (auto simp add: atLeastLessThan_def greaterThanLessThan_def)
paulson@14485
  1286
wenzelm@60758
  1287
subsubsection \<open>Finiteness\<close>
paulson@14485
  1288
paulson@15418
  1289
lemma image_atLeastZeroLessThan_int: "0 \<le> u ==>
nipkow@15045
  1290
    {(0::int)..<u} = int ` {..<nat u}"
paulson@14485
  1291
  apply (unfold image_def lessThan_def)
paulson@14485
  1292
  apply auto
paulson@14485
  1293
  apply (rule_tac x = "nat x" in exI)
huffman@35216
  1294
  apply (auto simp add: zless_nat_eq_int_zless [THEN sym])
paulson@14485
  1295
  done
paulson@14485
  1296
nipkow@15045
  1297
lemma finite_atLeastZeroLessThan_int: "finite {(0::int)..<u}"
wenzelm@47988
  1298
  apply (cases "0 \<le> u")
paulson@14485
  1299
  apply (subst image_atLeastZeroLessThan_int, assumption)
paulson@14485
  1300
  apply (rule finite_imageI)
paulson@14485
  1301
  apply auto
paulson@14485
  1302
  done
paulson@14485
  1303
nipkow@15045
  1304
lemma finite_atLeastLessThan_int [iff]: "finite {l..<u::int}"
nipkow@15045
  1305
  apply (subgoal_tac "(%x. x + l) ` {0..<u-l} = {l..<u}")
paulson@14485
  1306
  apply (erule subst)
paulson@14485
  1307
  apply (rule finite_imageI)
paulson@14485
  1308
  apply (rule finite_atLeastZeroLessThan_int)
nipkow@16733
  1309
  apply (rule image_add_int_atLeastLessThan)
paulson@14485
  1310
  done
paulson@14485
  1311
paulson@15418
  1312
lemma finite_atLeastAtMost_int [iff]: "finite {l..(u::int)}"
paulson@14485
  1313
  by (subst atLeastLessThanPlusOne_atLeastAtMost_int [THEN sym], simp)
paulson@14485
  1314
paulson@15418
  1315
lemma finite_greaterThanAtMost_int [iff]: "finite {l<..(u::int)}"
paulson@14485
  1316
  by (subst atLeastPlusOneAtMost_greaterThanAtMost_int [THEN sym], simp)
paulson@14485
  1317
paulson@15418
  1318
lemma finite_greaterThanLessThan_int [iff]: "finite {l<..<u::int}"
paulson@14485
  1319
  by (subst atLeastPlusOneLessThan_greaterThanLessThan_int [THEN sym], simp)
paulson@14485
  1320
nipkow@24853
  1321
wenzelm@60758
  1322
subsubsection \<open>Cardinality\<close>
paulson@14485
  1323
nipkow@15045
  1324
lemma card_atLeastZeroLessThan_int: "card {(0::int)..<u} = nat u"
wenzelm@47988
  1325
  apply (cases "0 \<le> u")
paulson@14485
  1326
  apply (subst image_atLeastZeroLessThan_int, assumption)
paulson@14485
  1327
  apply (subst card_image)
paulson@14485
  1328
  apply (auto simp add: inj_on_def)
paulson@14485
  1329
  done
paulson@14485
  1330
nipkow@15045
  1331
lemma card_atLeastLessThan_int [simp]: "card {l..<u} = nat (u - l)"
nipkow@15045
  1332
  apply (subgoal_tac "card {l..<u} = card {0..<u-l}")
paulson@14485
  1333
  apply (erule ssubst, rule card_atLeastZeroLessThan_int)
nipkow@15045
  1334
  apply (subgoal_tac "(%x. x + l) ` {0..<u-l} = {l..<u}")
paulson@14485
  1335
  apply (erule subst)
paulson@14485
  1336
  apply (rule card_image)
paulson@14485
  1337
  apply (simp add: inj_on_def)
nipkow@16733
  1338
  apply (rule image_add_int_atLeastLessThan)
paulson@14485
  1339
  done
paulson@14485
  1340
paulson@14485
  1341
lemma card_atLeastAtMost_int [simp]: "card {l..u} = nat (u - l + 1)"
nipkow@29667
  1342
apply (subst atLeastLessThanPlusOne_atLeastAtMost_int [THEN sym])
nipkow@29667
  1343
apply (auto simp add: algebra_simps)
nipkow@29667
  1344
done
paulson@14485
  1345
paulson@15418
  1346
lemma card_greaterThanAtMost_int [simp]: "card {l<..u} = nat (u - l)"
nipkow@29667
  1347
by (subst atLeastPlusOneAtMost_greaterThanAtMost_int [THEN sym], simp)
paulson@14485
  1348
nipkow@15045
  1349
lemma card_greaterThanLessThan_int [simp]: "card {l<..<u} = nat (u - (l + 1))"
nipkow@29667
  1350
by (subst atLeastPlusOneLessThan_greaterThanLessThan_int [THEN sym], simp)
paulson@14485
  1351
bulwahn@27656
  1352
lemma finite_M_bounded_by_nat: "finite {k. P k \<and> k < (i::nat)}"
bulwahn@27656
  1353
proof -
bulwahn@27656
  1354
  have "{k. P k \<and> k < i} \<subseteq> {..<i}" by auto
bulwahn@27656
  1355
  with finite_lessThan[of "i"] show ?thesis by (simp add: finite_subset)
bulwahn@27656
  1356
qed
bulwahn@27656
  1357
bulwahn@27656
  1358
lemma card_less:
bulwahn@27656
  1359
assumes zero_in_M: "0 \<in> M"
bulwahn@27656
  1360
shows "card {k \<in> M. k < Suc i} \<noteq> 0"
bulwahn@27656
  1361
proof -
bulwahn@27656
  1362
  from zero_in_M have "{k \<in> M. k < Suc i} \<noteq> {}" by auto
bulwahn@27656
  1363
  with finite_M_bounded_by_nat show ?thesis by (auto simp add: card_eq_0_iff)
bulwahn@27656
  1364
qed
bulwahn@27656
  1365
bulwahn@27656
  1366
lemma card_less_Suc2: "0 \<notin> M \<Longrightarrow> card {k. Suc k \<in> M \<and> k < i} = card {k \<in> M. k < Suc i}"
haftmann@37388
  1367
apply (rule card_bij_eq [of Suc _ _ "\<lambda>x. x - Suc 0"])
bulwahn@27656
  1368
apply auto
bulwahn@27656
  1369
apply (rule inj_on_diff_nat)
bulwahn@27656
  1370
apply auto
bulwahn@27656
  1371
apply (case_tac x)
bulwahn@27656
  1372
apply auto
bulwahn@27656
  1373
apply (case_tac xa)
bulwahn@27656
  1374
apply auto
bulwahn@27656
  1375
apply (case_tac xa)
bulwahn@27656
  1376
apply auto
bulwahn@27656
  1377
done
bulwahn@27656
  1378
bulwahn@27656
  1379
lemma card_less_Suc:
bulwahn@27656
  1380
  assumes zero_in_M: "0 \<in> M"
bulwahn@27656
  1381
    shows "Suc (card {k. Suc k \<in> M \<and> k < i}) = card {k \<in> M. k < Suc i}"
bulwahn@27656
  1382
proof -
bulwahn@27656
  1383
  from assms have a: "0 \<in> {k \<in> M. k < Suc i}" by simp
bulwahn@27656
  1384
  hence c: "{k \<in> M. k < Suc i} = insert 0 ({k \<in> M. k < Suc i} - {0})"
bulwahn@27656
  1385
    by (auto simp only: insert_Diff)
bulwahn@27656
  1386
  have b: "{k \<in> M. k < Suc i} - {0} = {k \<in> M - {0}. k < Suc i}"  by auto
hoelzl@62369
  1387
  from finite_M_bounded_by_nat[of "\<lambda>x. x \<in> M" "Suc i"]
lp15@57113
  1388
  have "Suc (card {k. Suc k \<in> M \<and> k < i}) = card (insert 0 ({k \<in> M. k < Suc i} - {0}))"
bulwahn@27656
  1389
    apply (subst card_insert)
bulwahn@27656
  1390
    apply simp_all
bulwahn@27656
  1391
    apply (subst b)
bulwahn@27656
  1392
    apply (subst card_less_Suc2[symmetric])
bulwahn@27656
  1393
    apply simp_all
bulwahn@27656
  1394
    done
bulwahn@27656
  1395
  with c show ?thesis by simp
bulwahn@27656
  1396
qed
bulwahn@27656
  1397
paulson@14485
  1398
wenzelm@60758
  1399
subsection \<open>Lemmas useful with the summation operator setsum\<close>
paulson@13850
  1400
wenzelm@60758
  1401
text \<open>For examples, see Algebra/poly/UnivPoly2.thy\<close>
ballarin@13735
  1402
wenzelm@60758
  1403
subsubsection \<open>Disjoint Unions\<close>
ballarin@13735
  1404
wenzelm@60758
  1405
text \<open>Singletons and open intervals\<close>
ballarin@13735
  1406
ballarin@13735
  1407
lemma ivl_disj_un_singleton:
nipkow@15045
  1408
  "{l::'a::linorder} Un {l<..} = {l..}"
nipkow@15045
  1409
  "{..<u} Un {u::'a::linorder} = {..u}"
nipkow@15045
  1410
  "(l::'a::linorder) < u ==> {l} Un {l<..<u} = {l..<u}"
nipkow@15045
  1411
  "(l::'a::linorder) < u ==> {l<..<u} Un {u} = {l<..u}"
nipkow@15045
  1412
  "(l::'a::linorder) <= u ==> {l} Un {l<..u} = {l..u}"
nipkow@15045
  1413
  "(l::'a::linorder) <= u ==> {l..<u} Un {u} = {l..u}"
ballarin@14398
  1414
by auto
ballarin@13735
  1415
wenzelm@60758
  1416
text \<open>One- and two-sided intervals\<close>
ballarin@13735
  1417
ballarin@13735
  1418
lemma ivl_disj_un_one:
nipkow@15045
  1419
  "(l::'a::linorder) < u ==> {..l} Un {l<..<u} = {..<u}"
nipkow@15045
  1420
  "(l::'a::linorder) <= u ==> {..<l} Un {l..<u} = {..<u}"
nipkow@15045
  1421
  "(l::'a::linorder) <= u ==> {..l} Un {l<..u} = {..u}"
nipkow@15045
  1422
  "(l::'a::linorder) <= u ==> {..<l} Un {l..u} = {..u}"
nipkow@15045
  1423
  "(l::'a::linorder) <= u ==> {l<..u} Un {u<..} = {l<..}"
nipkow@15045
  1424
  "(l::'a::linorder) < u ==> {l<..<u} Un {u..} = {l<..}"
nipkow@15045
  1425
  "(l::'a::linorder) <= u ==> {l..u} Un {u<..} = {l..}"
nipkow@15045
  1426
  "(l::'a::linorder) <= u ==> {l..<u} Un {u..} = {l..}"
ballarin@14398
  1427
by auto
ballarin@13735
  1428
wenzelm@60758
  1429
text \<open>Two- and two-sided intervals\<close>
ballarin@13735
  1430
ballarin@13735
  1431
lemma ivl_disj_un_two:
nipkow@15045
  1432
  "[| (l::'a::linorder) < m; m <= u |] ==> {l<..<m} Un {m..<u} = {l<..<u}"
nipkow@15045
  1433
  "[| (l::'a::linorder) <= m; m < u |] ==> {l<..m} Un {m<..<u} = {l<..<u}"
nipkow@15045
  1434
  "[| (l::'a::linorder) <= m; m <= u |] ==> {l..<m} Un {m..<u} = {l..<u}"
nipkow@15045
  1435
  "[| (l::'a::linorder) <= m; m < u |] ==> {l..m} Un {m<..<u} = {l..<u}"
nipkow@15045
  1436
  "[| (l::'a::linorder) < m; m <= u |] ==> {l<..<m} Un {m..u} = {l<..u}"
nipkow@15045
  1437
  "[| (l::'a::linorder) <= m; m <= u |] ==> {l<..m} Un {m<..u} = {l<..u}"
nipkow@15045
  1438
  "[| (l::'a::linorder) <= m; m <= u |] ==> {l..<m} Un {m..u} = {l..u}"
nipkow@15045
  1439
  "[| (l::'a::linorder) <= m; m <= u |] ==> {l..m} Un {m<..u} = {l..u}"
ballarin@14398
  1440
by auto
ballarin@13735
  1441
lp15@60150
  1442
lemma ivl_disj_un_two_touch:
lp15@60150
  1443
  "[| (l::'a::linorder) < m; m < u |] ==> {l<..m} Un {m..<u} = {l<..<u}"
lp15@60150
  1444
  "[| (l::'a::linorder) <= m; m < u |] ==> {l..m} Un {m..<u} = {l..<u}"
lp15@60150
  1445
  "[| (l::'a::linorder) < m; m <= u |] ==> {l<..m} Un {m..u} = {l<..u}"
lp15@60150
  1446
  "[| (l::'a::linorder) <= m; m <= u |] ==> {l..m} Un {m..u} = {l..u}"
lp15@60150
  1447
by auto
lp15@60150
  1448
lp15@60150
  1449
lemmas ivl_disj_un = ivl_disj_un_singleton ivl_disj_un_one ivl_disj_un_two ivl_disj_un_two_touch
ballarin@13735
  1450
wenzelm@60758
  1451
subsubsection \<open>Disjoint Intersections\<close>
ballarin@13735
  1452
wenzelm@60758
  1453
text \<open>One- and two-sided intervals\<close>
ballarin@13735
  1454
ballarin@13735
  1455
lemma ivl_disj_int_one:
nipkow@15045
  1456
  "{..l::'a::order} Int {l<..<u} = {}"
nipkow@15045
  1457
  "{..<l} Int {l..<u} = {}"
nipkow@15045
  1458
  "{..l} Int {l<..u} = {}"
nipkow@15045
  1459
  "{..<l} Int {l..u} = {}"
nipkow@15045
  1460
  "{l<..u} Int {u<..} = {}"
nipkow@15045
  1461
  "{l<..<u} Int {u..} = {}"
nipkow@15045
  1462
  "{l..u} Int {u<..} = {}"
nipkow@15045
  1463
  "{l..<u} Int {u..} = {}"
ballarin@14398
  1464
  by auto
ballarin@13735
  1465
wenzelm@60758
  1466
text \<open>Two- and two-sided intervals\<close>
ballarin@13735
  1467
ballarin@13735
  1468
lemma ivl_disj_int_two:
nipkow@15045
  1469
  "{l::'a::order<..<m} Int {m..<u} = {}"
nipkow@15045
  1470
  "{l<..m} Int {m<..<u} = {}"
nipkow@15045
  1471
  "{l..<m} Int {m..<u} = {}"
nipkow@15045
  1472
  "{l..m} Int {m<..<u} = {}"
nipkow@15045
  1473
  "{l<..<m} Int {m..u} = {}"
nipkow@15045
  1474
  "{l<..m} Int {m<..u} = {}"
nipkow@15045
  1475
  "{l..<m} Int {m..u} = {}"
nipkow@15045
  1476
  "{l..m} Int {m<..u} = {}"
ballarin@14398
  1477
  by auto
ballarin@13735
  1478
nipkow@32456
  1479
lemmas ivl_disj_int = ivl_disj_int_one ivl_disj_int_two
ballarin@13735
  1480
wenzelm@60758
  1481
subsubsection \<open>Some Differences\<close>
nipkow@15542
  1482
nipkow@15542
  1483
lemma ivl_diff[simp]:
nipkow@15542
  1484
 "i \<le> n \<Longrightarrow> {i..<m} - {i..<n} = {n..<(m::'a::linorder)}"
nipkow@15542
  1485
by(auto)
nipkow@15542
  1486
hoelzl@56194
  1487
lemma (in linorder) lessThan_minus_lessThan [simp]:
hoelzl@56194
  1488
  "{..< n} - {..< m} = {m ..< n}"
hoelzl@56194
  1489
  by auto
hoelzl@56194
  1490
paulson@60762
  1491
lemma (in linorder) atLeastAtMost_diff_ends:
paulson@60762
  1492
  "{a..b} - {a, b} = {a<..<b}"
paulson@60762
  1493
  by auto
paulson@60762
  1494
nipkow@15542
  1495
wenzelm@60758
  1496
subsubsection \<open>Some Subset Conditions\<close>
nipkow@15542
  1497
blanchet@54147
  1498
lemma ivl_subset [simp]:
nipkow@15542
  1499
 "({i..<j} \<subseteq> {m..<n}) = (j \<le> i | m \<le> i & j \<le> (n::'a::linorder))"
nipkow@15542
  1500
apply(auto simp:linorder_not_le)
nipkow@15542
  1501
apply(rule ccontr)
nipkow@15542
  1502
apply(insert linorder_le_less_linear[of i n])
nipkow@15542
  1503
apply(clarsimp simp:linorder_not_le)
nipkow@44890
  1504
apply(fastforce)
nipkow@15542
  1505
done
nipkow@15542
  1506
nipkow@15041
  1507
haftmann@63417
  1508
subsection \<open>Generic big monoid operation over intervals\<close>
haftmann@63417
  1509
haftmann@63417
  1510
lemma inj_on_add_nat' [simp]:
haftmann@63417
  1511
  "inj_on (plus k) N" for k :: nat
haftmann@63417
  1512
  by rule simp
haftmann@63417
  1513
haftmann@63417
  1514
context comm_monoid_set
haftmann@63417
  1515
begin
haftmann@63417
  1516
haftmann@63417
  1517
lemma atLeast_lessThan_shift_bounds:
haftmann@63417
  1518
  fixes m n k :: nat
haftmann@63417
  1519
  shows "F g {m + k..<n + k} = F (g \<circ> plus k) {m..<n}"
haftmann@63417
  1520
proof -
haftmann@63417
  1521
  have "{m + k..<n + k} = plus k ` {m..<n}"
haftmann@63417
  1522
    by (auto simp add: image_add_atLeastLessThan [symmetric])
haftmann@63417
  1523
  also have "F g (plus k ` {m..<n}) = F (g \<circ> plus k) {m..<n}"
haftmann@63417
  1524
    by (rule reindex) simp
haftmann@63417
  1525
  finally show ?thesis .
haftmann@63417
  1526
qed
haftmann@63417
  1527
haftmann@63417
  1528
lemma atLeast_atMost_shift_bounds:
haftmann@63417
  1529
  fixes m n k :: nat
haftmann@63417
  1530
  shows "F g {m + k..n + k} = F (g \<circ> plus k) {m..n}"
haftmann@63417
  1531
proof -
haftmann@63417
  1532
  have "{m + k..n + k} = plus k ` {m..n}"
haftmann@63417
  1533
    by (auto simp del: image_add_atLeastAtMost simp add: image_add_atLeastAtMost [symmetric])
haftmann@63417
  1534
  also have "F g (plus k ` {m..n}) = F (g \<circ> plus k) {m..n}"
haftmann@63417
  1535
    by (rule reindex) simp
haftmann@63417
  1536
  finally show ?thesis .
haftmann@63417
  1537
qed
haftmann@63417
  1538
haftmann@63417
  1539
lemma atLeast_Suc_lessThan_Suc_shift:
haftmann@63417
  1540
  "F g {Suc m..<Suc n} = F (g \<circ> Suc) {m..<n}"
haftmann@63417
  1541
  using atLeast_lessThan_shift_bounds [of _ _ 1] by simp
haftmann@63417
  1542
haftmann@63417
  1543
lemma atLeast_Suc_atMost_Suc_shift:
haftmann@63417
  1544
  "F g {Suc m..Suc n} = F (g \<circ> Suc) {m..n}"
haftmann@63417
  1545
  using atLeast_atMost_shift_bounds [of _ _ 1] by simp
haftmann@63417
  1546
haftmann@63417
  1547
lemma atLeast0_lessThan_Suc:
haftmann@63417
  1548
  "F g {0..<Suc n} = F g {0..<n} \<^bold>* g n"
haftmann@63417
  1549
  by (simp add: atLeast0_lessThan_Suc ac_simps)
haftmann@63417
  1550
haftmann@63417
  1551
lemma atLeast0_atMost_Suc:
haftmann@63417
  1552
  "F g {0..Suc n} = F g {0..n} \<^bold>* g (Suc n)"
haftmann@63417
  1553
  by (simp add: atLeast0_atMost_Suc ac_simps)
haftmann@63417
  1554
haftmann@63417
  1555
lemma atLeast0_lessThan_Suc_shift:
haftmann@63417
  1556
  "F g {0..<Suc n} = g 0 \<^bold>* F (g \<circ> Suc) {0..<n}"
haftmann@63417
  1557
  by (simp add: atLeast0_lessThan_Suc_eq_insert_0 atLeast_Suc_lessThan_Suc_shift)
haftmann@63417
  1558
haftmann@63417
  1559
lemma atLeast0_atMost_Suc_shift:
haftmann@63417
  1560
  "F g {0..Suc n} = g 0 \<^bold>* F (g \<circ> Suc) {0..n}"
haftmann@63417
  1561
  by (simp add: atLeast0_atMost_Suc_eq_insert_0 atLeast_Suc_atMost_Suc_shift)
haftmann@63417
  1562
haftmann@63417
  1563
lemma ivl_cong:
haftmann@63417
  1564
  "a = c \<Longrightarrow> b = d \<Longrightarrow> (\<And>x. c \<le> x \<Longrightarrow> x < d \<Longrightarrow> g x = h x)
haftmann@63417
  1565
    \<Longrightarrow> F g {a..<b} = F h {c..<d}"
haftmann@63417
  1566
  by (rule cong) simp_all
haftmann@63417
  1567
haftmann@63417
  1568
lemma atLeast_lessThan_shift_0:
haftmann@63417
  1569
  fixes m n p :: nat
haftmann@63417
  1570
  shows "F g {m..<n} = F (g \<circ> plus m) {0..<n - m}"
haftmann@63417
  1571
  using atLeast_lessThan_shift_bounds [of g 0 m "n - m"]
haftmann@63417
  1572
  by (cases "m \<le> n") simp_all
haftmann@63417
  1573
haftmann@63417
  1574
lemma atLeast_atMost_shift_0:
haftmann@63417
  1575
  fixes m n p :: nat
haftmann@63417
  1576
  assumes "m \<le> n"
haftmann@63417
  1577
  shows "F g {m..n} = F (g \<circ> plus m) {0..n - m}"
haftmann@63417
  1578
  using assms atLeast_atMost_shift_bounds [of g 0 m "n - m"] by simp
haftmann@63417
  1579
haftmann@63417
  1580
lemma atLeast_lessThan_concat:
haftmann@63417
  1581
  fixes m n p :: nat
haftmann@63417
  1582
  shows "m \<le> n \<Longrightarrow> n \<le> p \<Longrightarrow> F g {m..<n} \<^bold>* F g {n..<p} = F g {m..<p}"
haftmann@63417
  1583
  by (simp add: union_disjoint [symmetric] ivl_disj_un)
haftmann@63417
  1584
haftmann@63417
  1585
lemma atLeast_lessThan_rev:
haftmann@63417
  1586
  "F g {n..<m} = F (\<lambda>i. g (m + n - Suc i)) {n..<m}"
haftmann@63417
  1587
  by (rule reindex_bij_witness [where i="\<lambda>i. m + n - Suc i" and j="\<lambda>i. m + n - Suc i"], auto)
haftmann@63417
  1588
haftmann@63417
  1589
lemma atLeast_atMost_rev:
haftmann@63417
  1590
  fixes n m :: nat
haftmann@63417
  1591
  shows "F g {n..m} = F (\<lambda>i. g (m + n - i)) {n..m}"
haftmann@63417
  1592
  by (rule reindex_bij_witness [where i="\<lambda>i. m + n - i" and j="\<lambda>i. m + n - i"]) auto
haftmann@63417
  1593
haftmann@63417
  1594
lemma atLeast_lessThan_rev_at_least_Suc_atMost:
haftmann@63417
  1595
  "F g {n..<m} = F (\<lambda>i. g (m + n - i)) {Suc n..m}"
haftmann@63417
  1596
  unfolding atLeast_lessThan_rev [of g n m]
haftmann@63417
  1597
  by (cases m) (simp_all add: atLeast_Suc_atMost_Suc_shift atLeastLessThanSuc_atLeastAtMost)
haftmann@63417
  1598
haftmann@63417
  1599
end
haftmann@63417
  1600
haftmann@63417
  1601
wenzelm@60758
  1602
subsection \<open>Summation indexed over intervals\<close>
nipkow@15042
  1603
wenzelm@61955
  1604
syntax (ASCII)
wenzelm@61955
  1605
  "_from_to_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(SUM _ = _.._./ _)" [0,0,0,10] 10)
wenzelm@61955
  1606
  "_from_upto_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(SUM _ = _..<_./ _)" [0,0,0,10] 10)
wenzelm@61955
  1607
  "_upt_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(SUM _<_./ _)" [0,0,10] 10)
wenzelm@61955
  1608
  "_upto_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(SUM _<=_./ _)" [0,0,10] 10)
wenzelm@61955
  1609
nipkow@15056
  1610
syntax (latex_sum output)
nipkow@15052
  1611
  "_from_to_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
nipkow@15052
  1612
 ("(3\<^raw:$\sum_{>_ = _\<^raw:}^{>_\<^raw:}$> _)" [0,0,0,10] 10)
nipkow@15052
  1613
  "_from_upto_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
nipkow@15052
  1614
 ("(3\<^raw:$\sum_{>_ = _\<^raw:}^{<>_\<^raw:}$> _)" [0,0,0,10] 10)
nipkow@16052
  1615
  "_upt_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
nipkow@16052
  1616
 ("(3\<^raw:$\sum_{>_ < _\<^raw:}$> _)" [0,0,10] 10)
nipkow@15052
  1617
  "_upto_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
nipkow@16052
  1618
 ("(3\<^raw:$\sum_{>_ \<le> _\<^raw:}$> _)" [0,0,10] 10)
nipkow@15041
  1619
wenzelm@61955
  1620
syntax
wenzelm@61955
  1621
  "_from_to_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Sum>_ = _.._./ _)" [0,0,0,10] 10)
wenzelm@61955
  1622
  "_from_upto_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Sum>_ = _..<_./ _)" [0,0,0,10] 10)
wenzelm@61955
  1623
  "_upt_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Sum>_<_./ _)" [0,0,10] 10)
wenzelm@61955
  1624
  "_upto_setsum" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Sum>_\<le>_./ _)" [0,0,10] 10)
wenzelm@61955
  1625
nipkow@15048
  1626
translations
wenzelm@61955
  1627
  "\<Sum>x=a..b. t" == "CONST setsum (\<lambda>x. t) {a..b}"
wenzelm@61955
  1628
  "\<Sum>x=a..<b. t" == "CONST setsum (\<lambda>x. t) {a..<b}"
nipkow@28853
  1629
  "\<Sum>i\<le>n. t" == "CONST setsum (\<lambda>i. t) {..n}"
nipkow@28853
  1630
  "\<Sum>i<n. t" == "CONST setsum (\<lambda>i. t) {..<n}"
nipkow@15041
  1631
wenzelm@60758
  1632
text\<open>The above introduces some pretty alternative syntaxes for
nipkow@15056
  1633
summation over intervals:
nipkow@15052
  1634
\begin{center}
nipkow@15052
  1635
\begin{tabular}{lll}
nipkow@15056
  1636
Old & New & \LaTeX\\
nipkow@15056
  1637
@{term[source]"\<Sum>x\<in>{a..b}. e"} & @{term"\<Sum>x=a..b. e"} & @{term[mode=latex_sum]"\<Sum>x=a..b. e"}\\
nipkow@15056
  1638
@{term[source]"\<Sum>x\<in>{a..<b}. e"} & @{term"\<Sum>x=a..<b. e"} & @{term[mode=latex_sum]"\<Sum>x=a..<b. e"}\\
nipkow@16052
  1639
@{term[source]"\<Sum>x\<in>{..b}. e"} & @{term"\<Sum>x\<le>b. e"} & @{term[mode=latex_sum]"\<Sum>x\<le>b. e"}\\
nipkow@15056
  1640
@{term[source]"\<Sum>x\<in>{..<b}. e"} & @{term"\<Sum>x<b. e"} & @{term[mode=latex_sum]"\<Sum>x<b. e"}
nipkow@15052
  1641
\end{tabular}
nipkow@15052
  1642
\end{center}
nipkow@15056
  1643
The left column shows the term before introduction of the new syntax,
nipkow@15056
  1644
the middle column shows the new (default) syntax, and the right column
nipkow@15056
  1645
shows a special syntax. The latter is only meaningful for latex output
nipkow@15056
  1646
and has to be activated explicitly by setting the print mode to
wenzelm@61799
  1647
\<open>latex_sum\<close> (e.g.\ via \<open>mode = latex_sum\<close> in
nipkow@15056
  1648
antiquotations). It is not the default \LaTeX\ output because it only
nipkow@15056
  1649
works well with italic-style formulae, not tt-style.
nipkow@15052
  1650
nipkow@15052
  1651
Note that for uniformity on @{typ nat} it is better to use
wenzelm@61799
  1652
@{term"\<Sum>x::nat=0..<n. e"} rather than \<open>\<Sum>x<n. e\<close>: \<open>setsum\<close> may
nipkow@15052
  1653
not provide all lemmas available for @{term"{m..<n}"} also in the
wenzelm@60758
  1654
special form for @{term"{..<n}"}.\<close>
nipkow@15052
  1655
wenzelm@60758
  1656
text\<open>This congruence rule should be used for sums over intervals as
haftmann@57418
  1657
the standard theorem @{text[source]setsum.cong} does not work well
nipkow@15542
  1658
with the simplifier who adds the unsimplified premise @{term"x:B"} to
wenzelm@60758
  1659
the context.\<close>
nipkow@15542
  1660
haftmann@63417
  1661
lemmas setsum_ivl_cong = setsum.ivl_cong
nipkow@15041
  1662
nipkow@16041
  1663
(* FIXME why are the following simp rules but the corresponding eqns
nipkow@16041
  1664
on intervals are not? *)
nipkow@16041
  1665
haftmann@63417
  1666
lemma setsum_atMost_Suc [simp]:
haftmann@63417
  1667
  "(\<Sum>i \<le> Suc n. f i) = (\<Sum>i \<le> n. f i) + f (Suc n)"
haftmann@63417
  1668
  by (simp add: atMost_Suc ac_simps)
nipkow@16052
  1669
haftmann@63417
  1670
lemma setsum_lessThan_Suc [simp]:
haftmann@63417
  1671
  "(\<Sum>i < Suc n. f i) = (\<Sum>i < n. f i) + f n"
haftmann@63417
  1672
  by (simp add: lessThan_Suc ac_simps)
nipkow@15041
  1673
haftmann@63417
  1674
lemma setsum_cl_ivl_Suc [simp]:
nipkow@15561
  1675
  "setsum f {m..Suc n} = (if Suc n < m then 0 else setsum f {m..n} + f(Suc n))"
haftmann@63417
  1676
  by (auto simp: ac_simps atLeastAtMostSuc_conv)
nipkow@15561
  1677
haftmann@63417
  1678
lemma setsum_op_ivl_Suc [simp]:
nipkow@15561
  1679
  "setsum f {m..<Suc n} = (if n < m then 0 else setsum f {m..<n} + f(n))"
haftmann@63417
  1680
  by (auto simp: ac_simps atLeastLessThanSuc)
nipkow@16041
  1681
(*
nipkow@15561
  1682
lemma setsum_cl_ivl_add_one_nat: "(n::nat) <= m + 1 ==>
nipkow@15561
  1683
    (\<Sum>i=n..m+1. f i) = (\<Sum>i=n..m. f i) + f(m + 1)"
haftmann@57514
  1684
by (auto simp:ac_simps atLeastAtMostSuc_conv)
nipkow@16041
  1685
*)
nipkow@28068
  1686
nipkow@28068
  1687
lemma setsum_head:
nipkow@28068
  1688
  fixes n :: nat
hoelzl@62369
  1689
  assumes mn: "m <= n"
nipkow@28068
  1690
  shows "(\<Sum>x\<in>{m..n}. P x) = P m + (\<Sum>x\<in>{m<..n}. P x)" (is "?lhs = ?rhs")
nipkow@28068
  1691
proof -
nipkow@28068
  1692
  from mn
nipkow@28068
  1693
  have "{m..n} = {m} \<union> {m<..n}"
nipkow@28068
  1694
    by (auto intro: ivl_disj_un_singleton)
nipkow@28068
  1695
  hence "?lhs = (\<Sum>x\<in>{m} \<union> {m<..n}. P x)"
nipkow@28068
  1696
    by (simp add: atLeast0LessThan)
nipkow@28068
  1697
  also have "\<dots> = ?rhs" by simp
nipkow@28068
  1698
  finally show ?thesis .
nipkow@28068
  1699
qed
nipkow@28068
  1700
nipkow@28068
  1701
lemma setsum_head_Suc:
nipkow@28068
  1702
  "m \<le> n \<Longrightarrow> setsum f {m..n} = f m + setsum f {Suc m..n}"
nipkow@28068
  1703
by (simp add: setsum_head atLeastSucAtMost_greaterThanAtMost)
nipkow@28068
  1704
nipkow@28068
  1705
lemma setsum_head_upt_Suc:
nipkow@28068
  1706
  "m < n \<Longrightarrow> setsum f {m..<n} = f m + setsum f {Suc m..<n}"
huffman@30079
  1707
apply(insert setsum_head_Suc[of m "n - Suc 0" f])
nipkow@29667
  1708
apply (simp add: atLeastLessThanSuc_atLeastAtMost[symmetric] algebra_simps)
nipkow@28068
  1709
done
nipkow@28068
  1710
nipkow@31501
  1711
lemma setsum_ub_add_nat: assumes "(m::nat) \<le> n + 1"
nipkow@31501
  1712
  shows "setsum f {m..n + p} = setsum f {m..n} + setsum f {n + 1..n + p}"
nipkow@31501
  1713
proof-
wenzelm@60758
  1714
  have "{m .. n+p} = {m..n} \<union> {n+1..n+p}" using \<open>m \<le> n+1\<close> by auto
haftmann@57418
  1715
  thus ?thesis by (auto simp: ivl_disj_int setsum.union_disjoint
nipkow@31501
  1716
    atLeastSucAtMost_greaterThanAtMost)
nipkow@31501
  1717
qed
nipkow@28068
  1718
haftmann@63417
  1719
lemmas setsum_add_nat_ivl = setsum.atLeast_lessThan_concat
nipkow@15539
  1720
nipkow@15539
  1721
lemma setsum_diff_nat_ivl:
nipkow@15539
  1722
fixes f :: "nat \<Rightarrow> 'a::ab_group_add"
nipkow@15539
  1723
shows "\<lbrakk> m \<le> n; n \<le> p \<rbrakk> \<Longrightarrow>
nipkow@15539
  1724
  setsum f {m..<p} - setsum f {m..<n} = setsum f {n..<p}"
nipkow@15539
  1725
using setsum_add_nat_ivl [of m n p f,symmetric]
haftmann@57514
  1726
apply (simp add: ac_simps)
nipkow@15539
  1727
done
nipkow@15539
  1728
nipkow@31505
  1729
lemma setsum_natinterval_difff:
nipkow@31505
  1730
  fixes f:: "nat \<Rightarrow> ('a::ab_group_add)"
nipkow@31505
  1731
  shows  "setsum (\<lambda>k. f k - f(k + 1)) {(m::nat) .. n} =
nipkow@31505
  1732
          (if m <= n then f m - f(n + 1) else 0)"
nipkow@31505
  1733
by (induct n, auto simp add: algebra_simps not_le le_Suc_eq)
nipkow@31505
  1734
hoelzl@56194
  1735
lemma setsum_nat_group: "(\<Sum>m<n::nat. setsum f {m * k ..< m*k + k}) = setsum f {..< n * k}"
hoelzl@56194
  1736
  apply (subgoal_tac "k = 0 | 0 < k", auto)
hoelzl@56194
  1737
  apply (induct "n")
haftmann@57512
  1738
  apply (simp_all add: setsum_add_nat_ivl add.commute atLeast0LessThan[symmetric])
hoelzl@56194
  1739
  done
nipkow@28068
  1740
lp15@60150
  1741
lemma setsum_triangle_reindex:
lp15@60150
  1742
  fixes n :: nat
lp15@60150
  1743
  shows "(\<Sum>(i,j)\<in>{(i,j). i+j < n}. f i j) = (\<Sum>k<n. \<Sum>i\<le>k. f i (k - i))"
lp15@60150
  1744
  apply (simp add: setsum.Sigma)
lp15@60150
  1745
  apply (rule setsum.reindex_bij_witness[where j="\<lambda>(i, j). (i+j, i)" and i="\<lambda>(k, i). (i, k - i)"])
lp15@60150
  1746
  apply auto
lp15@60150
  1747
  done
lp15@60150
  1748
lp15@60150
  1749
lemma setsum_triangle_reindex_eq:
lp15@60150
  1750
  fixes n :: nat
lp15@60150
  1751
  shows "(\<Sum>(i,j)\<in>{(i,j). i+j \<le> n}. f i j) = (\<Sum>k\<le>n. \<Sum>i\<le>k. f i (k - i))"
lp15@60150
  1752
using setsum_triangle_reindex [of f "Suc n"]
lp15@60150
  1753
by (simp only: Nat.less_Suc_eq_le lessThan_Suc_atMost)
lp15@60150
  1754
lp15@60162
  1755
lemma nat_diff_setsum_reindex: "(\<Sum>i<n. f (n - Suc i)) = (\<Sum>i<n. f i)"
lp15@60162
  1756
  by (rule setsum.reindex_bij_witness[where i="\<lambda>i. n - Suc i" and j="\<lambda>i. n - Suc i"]) auto
lp15@60162
  1757
haftmann@63417
  1758
haftmann@63417
  1759
subsubsection \<open>Shifting bounds\<close>
nipkow@16733
  1760
nipkow@15539
  1761
lemma setsum_shift_bounds_nat_ivl:
nipkow@15539
  1762
  "setsum f {m+k..<n+k} = setsum (%i. f(i + k)){m..<n::nat}"
nipkow@15539
  1763
by (induct "n", auto simp:atLeastLessThanSuc)
nipkow@15539
  1764
nipkow@16733
  1765
lemma setsum_shift_bounds_cl_nat_ivl:
nipkow@16733
  1766
  "setsum f {m+k..n+k} = setsum (%i. f(i + k)){m..n::nat}"
hoelzl@57129
  1767
  by (rule setsum.reindex_bij_witness[where i="\<lambda>i. i + k" and j="\<lambda>i. i - k"]) auto
nipkow@16733
  1768
nipkow@16733
  1769
corollary setsum_shift_bounds_cl_Suc_ivl:
nipkow@16733
  1770
  "setsum f {Suc m..Suc n} = setsum (%i. f(Suc i)){m..n}"
huffman@30079
  1771
by (simp add:setsum_shift_bounds_cl_nat_ivl[where k="Suc 0", simplified])
nipkow@16733
  1772
nipkow@16733
  1773
corollary setsum_shift_bounds_Suc_ivl:
nipkow@16733
  1774
  "setsum f {Suc m..<Suc n} = setsum (%i. f(Suc i)){m..<n}"
huffman@30079
  1775
by (simp add:setsum_shift_bounds_nat_ivl[where k="Suc 0", simplified])
nipkow@16733
  1776
nipkow@28068
  1777
lemma setsum_shift_lb_Suc0_0:
nipkow@28068
  1778
  "f(0::nat) = (0::nat) \<Longrightarrow> setsum f {Suc 0..k} = setsum f {0..k}"
nipkow@28068
  1779
by(simp add:setsum_head_Suc)
kleing@19106
  1780
nipkow@28068
  1781
lemma setsum_shift_lb_Suc0_0_upt:
nipkow@28068
  1782
  "f(0::nat) = 0 \<Longrightarrow> setsum f {Suc 0..<k} = setsum f {0..<k}"
nipkow@28068
  1783
apply(cases k)apply simp
nipkow@28068
  1784
apply(simp add:setsum_head_upt_Suc)
nipkow@28068
  1785
done
kleing@19022
  1786
haftmann@52380
  1787
lemma setsum_atMost_Suc_shift:
haftmann@52380
  1788
  fixes f :: "nat \<Rightarrow> 'a::comm_monoid_add"
haftmann@52380
  1789
  shows "(\<Sum>i\<le>Suc n. f i) = f 0 + (\<Sum>i\<le>n. f (Suc i))"
haftmann@52380
  1790
proof (induct n)
haftmann@52380
  1791
  case 0 show ?case by simp
haftmann@52380
  1792
next
haftmann@52380
  1793
  case (Suc n) note IH = this
haftmann@52380
  1794
  have "(\<Sum>i\<le>Suc (Suc n). f i) = (\<Sum>i\<le>Suc n. f i) + f (Suc (Suc n))"
haftmann@52380
  1795
    by (rule setsum_atMost_Suc)
haftmann@52380
  1796
  also have "(\<Sum>i\<le>Suc n. f i) = f 0 + (\<Sum>i\<le>n. f (Suc i))"
haftmann@52380
  1797
    by (rule IH)
haftmann@52380
  1798
  also have "f 0 + (\<Sum>i\<le>n. f (Suc i)) + f (Suc (Suc n)) =
haftmann@52380
  1799
             f 0 + ((\<Sum>i\<le>n. f (Suc i)) + f (Suc (Suc n)))"
haftmann@57512
  1800
    by (rule add.assoc)
haftmann@52380
  1801
  also have "(\<Sum>i\<le>n. f (Suc i)) + f (Suc (Suc n)) = (\<Sum>i\<le>Suc n. f (Suc i))"
haftmann@52380
  1802
    by (rule setsum_atMost_Suc [symmetric])
haftmann@52380
  1803
  finally show ?case .
haftmann@52380
  1804
qed
haftmann@52380
  1805
eberlm@63099
  1806
lemma setsum_lessThan_Suc_shift:
eberlm@63099
  1807
  "(\<Sum>i<Suc n. f i) = f 0 + (\<Sum>i<n. f (Suc i))"
eberlm@63099
  1808
  by (induction n) (simp_all add: add_ac)
eberlm@63099
  1809
lp15@62379
  1810
lemma setsum_atMost_shift:
lp15@62379
  1811
  fixes f :: "nat \<Rightarrow> 'a::comm_monoid_add"
lp15@62379
  1812
  shows "(\<Sum>i\<le>n. f i) = f 0 + (\<Sum>i<n. f (Suc i))"
lp15@62379
  1813
by (metis atLeast0AtMost atLeast0LessThan atLeastLessThanSuc_atLeastAtMost atLeastSucAtMost_greaterThanAtMost le0 setsum_head setsum_shift_bounds_Suc_ivl)
lp15@62379
  1814
lp15@56238
  1815
lemma setsum_last_plus: fixes n::nat shows "m <= n \<Longrightarrow> (\<Sum>i = m..n. f i) = f n + (\<Sum>i = m..<n. f i)"
haftmann@57512
  1816
  by (cases n) (auto simp: atLeastLessThanSuc_atLeastAtMost add.commute)
lp15@56238
  1817
lp15@56238
  1818
lemma setsum_Suc_diff:
lp15@56238
  1819
  fixes f :: "nat \<Rightarrow> 'a::ab_group_add"
lp15@56238
  1820
  assumes "m \<le> Suc n"
lp15@56238
  1821
  shows "(\<Sum>i = m..n. f(Suc i) - f i) = f (Suc n) - f m"
lp15@56238
  1822
using assms by (induct n) (auto simp: le_Suc_eq)
lp15@55718
  1823
lp15@55718
  1824
lemma nested_setsum_swap:
lp15@55718
  1825
     "(\<Sum>i = 0..n. (\<Sum>j = 0..<i. a i j)) = (\<Sum>j = 0..<n. \<Sum>i = Suc j..n. a i j)"
haftmann@57418
  1826
  by (induction n) (auto simp: setsum.distrib)
lp15@55718
  1827
lp15@56215
  1828
lemma nested_setsum_swap':
lp15@56215
  1829
     "(\<Sum>i\<le>n. (\<Sum>j<i. a i j)) = (\<Sum>j<n. \<Sum>i = Suc j..n. a i j)"
haftmann@57418
  1830
  by (induction n) (auto simp: setsum.distrib)
lp15@56215
  1831
haftmann@63365
  1832
lemma setsum_atLeast1_atMost_eq:
haftmann@63365
  1833
  "setsum f {Suc 0..n} = (\<Sum>k<n. f (Suc k))"
haftmann@63365
  1834
proof -
haftmann@63365
  1835
  have "setsum f {Suc 0..n} = setsum f (Suc ` {..<n})"
haftmann@63365
  1836
    by (simp add: image_Suc_lessThan)
haftmann@63365
  1837
  also have "\<dots> = (\<Sum>k<n. f (Suc k))"
haftmann@63365
  1838
    by (simp add: setsum.reindex)
haftmann@63365
  1839
  finally show ?thesis .
haftmann@63365
  1840
qed
lp15@56238
  1841
haftmann@52380
  1842
haftmann@63417
  1843
subsubsection \<open>Telescoping\<close>
eberlm@61524
  1844
eberlm@61524
  1845
lemma setsum_telescope:
eberlm@61524
  1846
  fixes f::"nat \<Rightarrow> 'a::ab_group_add"
eberlm@61524
  1847
  shows "setsum (\<lambda>i. f i - f (Suc i)) {.. i} = f 0 - f (Suc i)"
eberlm@61524
  1848
  by (induct i) simp_all
eberlm@61524
  1849
eberlm@61524
  1850
lemma setsum_telescope'':
eberlm@61524
  1851
  assumes "m \<le> n"
eberlm@61524
  1852
  shows   "(\<Sum>k\<in>{Suc m..n}. f k - f (k - 1)) = f n - (f m :: 'a :: ab_group_add)"
eberlm@61524
  1853
  by (rule dec_induct[OF assms]) (simp_all add: algebra_simps)
eberlm@61524
  1854
eberlm@63721
  1855
lemma setsum_lessThan_telescope:
eberlm@63721
  1856
  "(\<Sum>n<m. f (Suc n) - f n :: 'a :: ab_group_add) = f m - f 0"
eberlm@63721
  1857
  by (induction m) (simp_all add: algebra_simps)
eberlm@63721
  1858
eberlm@63721
  1859
lemma setsum_lessThan_telescope':
eberlm@63721
  1860
  "(\<Sum>n<m. f n - f (Suc n) :: 'a :: ab_group_add) = f 0 - f m"
eberlm@63721
  1861
  by (induction m) (simp_all add: algebra_simps)
eberlm@63721
  1862
haftmann@63417
  1863
haftmann@63417
  1864
subsubsection \<open>The formula for geometric sums\<close>
ballarin@17149
  1865
ballarin@17149
  1866
lemma geometric_sum:
haftmann@36307
  1867
  assumes "x \<noteq> 1"
hoelzl@56193
  1868
  shows "(\<Sum>i<n. x ^ i) = (x ^ n - 1) / (x - 1::'a::field)"
haftmann@36307
  1869
proof -
haftmann@36307
  1870
  from assms obtain y where "y = x - 1" and "y \<noteq> 0" by simp_all
hoelzl@56193
  1871
  moreover have "(\<Sum>i<n. (y + 1) ^ i) = ((y + 1) ^ n - 1) / y"
haftmann@63417
  1872
    by (induct n) (simp_all add: field_simps \<open>y \<noteq> 0\<close>)
haftmann@36307
  1873
  ultimately show ?thesis by simp
haftmann@36307
  1874
qed
haftmann@36307
  1875
lp15@60162
  1876
lemma diff_power_eq_setsum:
lp15@60162
  1877
  fixes y :: "'a::{comm_ring,monoid_mult}"
lp15@60162
  1878
  shows
lp15@60162
  1879
    "x ^ (Suc n) - y ^ (Suc n) =
lp15@60162
  1880
      (x - y) * (\<Sum>p<Suc n. (x ^ p) * y ^ (n - p))"
lp15@60162
  1881
proof (induct n)
lp15@60162
  1882
  case (Suc n)
lp15@60162
  1883
  have "x ^ Suc (Suc n) - y ^ Suc (Suc n) = x * (x * x^n) - y * (y * y ^ n)"
haftmann@63417
  1884
    by simp
lp15@60162
  1885
  also have "... = y * (x ^ (Suc n) - y ^ (Suc n)) + (x - y) * (x * x^n)"
haftmann@63417
  1886
    by (simp add: algebra_simps)
lp15@60162
  1887
  also have "... = y * ((x - y) * (\<Sum>p<Suc n. (x ^ p) * y ^ (n - p))) + (x - y) * (x * x^n)"
lp15@60162
  1888
    by (simp only: Suc)
lp15@60162
  1889
  also have "... = (x - y) * (y * (\<Sum>p<Suc n. (x ^ p) * y ^ (n - p))) + (x - y) * (x * x^n)"
lp15@60162
  1890
    by (simp only: mult.left_commute)
lp15@60162
  1891
  also have "... = (x - y) * (\<Sum>p<Suc (Suc n). x ^ p * y ^ (Suc n - p))"
haftmann@63417
  1892
    by (simp add: field_simps Suc_diff_le setsum_left_distrib setsum_right_distrib)
lp15@60162
  1893
  finally show ?case .
lp15@60162
  1894
qed simp
lp15@60162
  1895
wenzelm@61799
  1896
corollary power_diff_sumr2: \<comment>\<open>\<open>COMPLEX_POLYFUN\<close> in HOL Light\<close>
lp15@60162
  1897
  fixes x :: "'a::{comm_ring,monoid_mult}"
lp15@60162
  1898
  shows   "x^n - y^n = (x - y) * (\<Sum>i<n. y^(n - Suc i) * x^i)"
lp15@60162
  1899
using diff_power_eq_setsum[of x "n - 1" y]
lp15@60162
  1900
by (cases "n = 0") (simp_all add: field_simps)
lp15@60162
  1901
lp15@60162
  1902
lemma power_diff_1_eq:
lp15@60162
  1903
  fixes x :: "'a::{comm_ring,monoid_mult}"
lp15@60162
  1904
  shows "n \<noteq> 0 \<Longrightarrow> x^n - 1 = (x - 1) * (\<Sum>i<n. (x^i))"
lp15@60162
  1905
using diff_power_eq_setsum [of x _ 1]
lp15@60162
  1906
  by (cases n) auto
lp15@60162
  1907
lp15@60162
  1908
lemma one_diff_power_eq':
lp15@60162
  1909
  fixes x :: "'a::{comm_ring,monoid_mult}"
lp15@60162
  1910
  shows "n \<noteq> 0 \<Longrightarrow> 1 - x^n = (1 - x) * (\<Sum>i<n. x^(n - Suc i))"
lp15@60162
  1911
using diff_power_eq_setsum [of 1 _ x]
lp15@60162
  1912
  by (cases n) auto
lp15@60162
  1913
lp15@60162
  1914
lemma one_diff_power_eq:
lp15@60162
  1915
  fixes x :: "'a::{comm_ring,monoid_mult}"
lp15@60162
  1916
  shows "n \<noteq> 0 \<Longrightarrow> 1 - x^n = (1 - x) * (\<Sum>i<n. x^i)"
lp15@60162
  1917
by (metis one_diff_power_eq' [of n x] nat_diff_setsum_reindex)
lp15@60162
  1918
ballarin@17149
  1919
haftmann@63417
  1920
subsubsection \<open>The formula for arithmetic sums\<close>
kleing@19469
  1921
huffman@47222
  1922
lemma gauss_sum:
hoelzl@56193
  1923
  "(2::'a::comm_semiring_1)*(\<Sum>i\<in>{1..n}. of_nat i) = of_nat n*((of_nat n)+1)"
kleing@19469
  1924
proof (induct n)
kleing@19469
  1925
  case 0
kleing@19469
  1926
  show ?case by simp
kleing@19469
  1927
next
kleing@19469
  1928
  case (Suc n)
huffman@47222
  1929
  then show ?case
huffman@47222
  1930
    by (simp add: algebra_simps add: one_add_one [symmetric] del: one_add_one)
huffman@47222
  1931
      (* FIXME: make numeral cancellation simprocs work for semirings *)
kleing@19469
  1932
qed
kleing@19469
  1933
kleing@19469
  1934
theorem arith_series_general:
huffman@47222
  1935
  "(2::'a::comm_semiring_1) * (\<Sum>i\<in>{..<n}. a + of_nat i * d) =
kleing@19469
  1936
  of_nat n * (a + (a + of_nat(n - 1)*d))"
kleing@19469
  1937
proof cases
kleing@19469
  1938
  assume ngt1: "n > 1"
kleing@19469
  1939
  let ?I = "\<lambda>i. of_nat i" and ?n = "of_nat n"
kleing@19469
  1940
  have
kleing@19469
  1941
    "(\<Sum>i\<in>{..<n}. a+?I i*d) =
kleing@19469
  1942
     ((\<Sum>i\<in>{..<n}. a) + (\<Sum>i\<in>{..<n}. ?I i*d))"
haftmann@57418
  1943
    by (rule setsum.distrib)
kleing@19469
  1944
  also from ngt1 have "\<dots> = ?n*a + (\<Sum>i\<in>{..<n}. ?I i*d)" by simp
kleing@19469
  1945
  also from ngt1 have "\<dots> = (?n*a + d*(\<Sum>i\<in>{1..<n}. ?I i))"
huffman@30079
  1946
    unfolding One_nat_def
haftmann@57514
  1947
    by (simp add: setsum_right_distrib atLeast0LessThan[symmetric] setsum_shift_lb_Suc0_0_upt ac_simps)
huffman@47222
  1948
  also have "2*\<dots> = 2*?n*a + d*2*(\<Sum>i\<in>{1..<n}. ?I i)"
huffman@47222
  1949
    by (simp add: algebra_simps)
kleing@19469
  1950
  also from ngt1 have "{1..<n} = {1..n - 1}"
nipkow@28068
  1951
    by (cases n) (auto simp: atLeastLessThanSuc_atLeastAtMost)
nipkow@28068
  1952
  also from ngt1
huffman@47222
  1953
  have "2*?n*a + d*2*(\<Sum>i\<in>{1..n - 1}. ?I i) = (2*?n*a + d*?I (n - 1)*?I n)"
haftmann@57514
  1954
    by (simp only: mult.assoc gauss_sum [of "n - 1"], unfold One_nat_def)
haftmann@57514
  1955
      (simp add:  mult.commute trans [OF add.commute of_nat_Suc [symmetric]])
huffman@47222
  1956
  finally show ?thesis
huffman@47222
  1957
    unfolding mult_2 by (simp add: algebra_simps)
kleing@19469
  1958
next
kleing@19469
  1959
  assume "\<not>(n > 1)"
kleing@19469
  1960
  hence "n = 1 \<or> n = 0" by auto
huffman@47222
  1961
  thus ?thesis by (auto simp: mult_2)
kleing@19469
  1962
qed
kleing@19469
  1963
kleing@19469
  1964
lemma arith_series_nat:
huffman@47222
  1965
  "(2::nat) * (\<Sum>i\<in>{..<n}. a+i*d) = n * (a + (a+(n - 1)*d))"
kleing@19469
  1966
proof -
kleing@19469
  1967
  have
huffman@47222
  1968
    "2 * (\<Sum>i\<in>{..<n::nat}. a + of_nat(i)*d) =
kleing@19469
  1969
    of_nat(n) * (a + (a + of_nat(n - 1)*d))"
kleing@19469
  1970
    by (rule arith_series_general)
huffman@30079
  1971
  thus ?thesis
huffman@35216
  1972
    unfolding One_nat_def by auto
kleing@19469
  1973
qed
kleing@19469
  1974
kleing@19469
  1975
lemma arith_series_int:
huffman@47222
  1976
  "2 * (\<Sum>i\<in>{..<n}. a + int i * d) = int n * (a + (a + int(n - 1)*d))"
huffman@47222
  1977
  by (fact arith_series_general) (* FIXME: duplicate *)
paulson@15418
  1978
hoelzl@59416
  1979
lemma sum_diff_distrib: "\<forall>x. Q x \<le> P x  \<Longrightarrow> (\<Sum>x<n. P x) - (\<Sum>x<n. Q x) = (\<Sum>x<n. P x - Q x :: nat)"
hoelzl@59416
  1980
  by (subst setsum_subtractf_nat) auto
kleing@19022
  1981
wenzelm@61955
  1982
haftmann@63417
  1983
subsubsection \<open>Division remainder\<close>
haftmann@63417
  1984
haftmann@63417
  1985
lemma range_mod:
haftmann@63417
  1986
  fixes n :: nat
haftmann@63417
  1987
  assumes "n > 0"
haftmann@63417
  1988
  shows "range (\<lambda>m. m mod n) = {0..<n}" (is "?A = ?B")
haftmann@63417
  1989
proof (rule set_eqI)
haftmann@63417
  1990
  fix m
haftmann@63417
  1991
  show "m \<in> ?A \<longleftrightarrow> m \<in> ?B"
haftmann@63417
  1992
  proof
haftmann@63417
  1993
    assume "m \<in> ?A"
haftmann@63417
  1994
    with assms show "m \<in> ?B"
wenzelm@63915
  1995
      by auto
haftmann@63417
  1996
  next
haftmann@63417
  1997
    assume "m \<in> ?B"
haftmann@63417
  1998
    moreover have "m mod n \<in> ?A"
haftmann@63417
  1999
      by (rule rangeI)
haftmann@63417
  2000
    ultimately show "m \<in> ?A"
haftmann@63417
  2001
      by simp
haftmann@63417
  2002
  qed
haftmann@63417
  2003
qed
haftmann@63417
  2004
haftmann@63417
  2005
wenzelm@60758
  2006
subsection \<open>Products indexed over intervals\<close>
paulson@29960
  2007
wenzelm@61955
  2008
syntax (ASCII)
wenzelm@61955
  2009
  "_from_to_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(PROD _ = _.._./ _)" [0,0,0,10] 10)
wenzelm@61955
  2010
  "_from_upto_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(PROD _ = _..<_./ _)" [0,0,0,10] 10)
wenzelm@61955
  2011
  "_upt_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(PROD _<_./ _)" [0,0,10] 10)
wenzelm@61955
  2012
  "_upto_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(PROD _<=_./ _)" [0,0,10] 10)
wenzelm@61955
  2013
paulson@29960
  2014
syntax (latex_prod output)
paulson@29960
  2015
  "_from_to_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
paulson@29960
  2016
 ("(3\<^raw:$\prod_{>_ = _\<^raw:}^{>_\<^raw:}$> _)" [0,0,0,10] 10)
paulson@29960
  2017
  "_from_upto_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
paulson@29960
  2018
 ("(3\<^raw:$\prod_{>_ = _\<^raw:}^{<>_\<^raw:}$> _)" [0,0,0,10] 10)
paulson@29960
  2019
  "_upt_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
paulson@29960
  2020
 ("(3\<^raw:$\prod_{>_ < _\<^raw:}$> _)" [0,0,10] 10)
paulson@29960
  2021
  "_upto_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"
paulson@29960
  2022
 ("(3\<^raw:$\prod_{>_ \<le> _\<^raw:}$> _)" [0,0,10] 10)
paulson@29960
  2023
wenzelm@61955
  2024
syntax
wenzelm@61955
  2025
  "_from_to_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Prod>_ = _.._./ _)" [0,0,0,10] 10)
wenzelm@61955
  2026
  "_from_upto_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Prod>_ = _..<_./ _)" [0,0,0,10] 10)
wenzelm@61955
  2027
  "_upt_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Prod>_<_./ _)" [0,0,10] 10)
wenzelm@61955
  2028
  "_upto_setprod" :: "idt \<Rightarrow> 'a \<Rightarrow> 'b \<Rightarrow> 'b"  ("(3\<Prod>_\<le>_./ _)" [0,0,10] 10)
wenzelm@61955
  2029
paulson@29960
  2030
translations
wenzelm@61955
  2031
  "\<Prod>x=a..b. t" \<rightleftharpoons> "CONST setprod (\<lambda>x. t) {a..b}"
wenzelm@61955
  2032
  "\<Prod>x=a..<b. t" \<rightleftharpoons> "CONST setprod (\<lambda>x. t) {a..<b}"
wenzelm@61955
  2033
  "\<Prod>i\<le>n. t" \<rightleftharpoons> "CONST setprod (\<lambda>i. t) {..n}"
wenzelm@61955
  2034
  "\<Prod>i<n. t" \<rightleftharpoons> "CONST setprod (\<lambda>i. t) {..<n}"
wenzelm@61955
  2035
lp15@55242
  2036
lemma setprod_int_plus_eq: "setprod int {i..i+j} =  \<Prod>{int i..int (i+j)}"
lp15@55242
  2037
  by (induct j) (auto simp add: atLeastAtMostSuc_conv atLeastAtMostPlus1_int_conv)
lp15@55242
  2038
lp15@55242
  2039
lemma setprod_int_eq: "setprod int {i..j} =  \<Prod>{int i..int j}"
lp15@55242
  2040
proof (cases "i \<le> j")
lp15@55242
  2041
  case True
lp15@55242
  2042
  then show ?thesis
hoelzl@62376
  2043
    by (metis le_iff_add setprod_int_plus_eq)
lp15@55242
  2044
next
lp15@55242
  2045
  case False
lp15@55242
  2046
  then show ?thesis
lp15@55242
  2047
    by auto
lp15@55242
  2048
qed
lp15@55242
  2049
eberlm@61524
  2050
haftmann@63417
  2051
subsubsection \<open>Shifting bounds\<close>
eberlm@61524
  2052
eberlm@61524
  2053
lemma setprod_shift_bounds_nat_ivl:
eberlm@61524
  2054
  "setprod f {m+k..<n+k} = setprod (%i. f(i + k)){m..<n::nat}"
eberlm@61524
  2055
by (induct "n", auto simp:atLeastLessThanSuc)
eberlm@61524
  2056
eberlm@61524
  2057
lemma setprod_shift_bounds_cl_nat_ivl:
eberlm@61524
  2058
  "setprod f {m+k..n+k} = setprod (%i. f(i + k)){m..n::nat}"
eberlm@61524
  2059
  by (rule setprod.reindex_bij_witness[where i="\<lambda>i. i + k" and j="\<lambda>i. i - k"]) auto
eberlm@61524
  2060
eberlm@61524
  2061
corollary setprod_shift_bounds_cl_Suc_ivl:
eberlm@61524
  2062
  "setprod f {Suc m..Suc n} = setprod (%i. f(Suc i)){m..n}"
eberlm@61524
  2063
by (simp add:setprod_shift_bounds_cl_nat_ivl[where k="Suc 0", simplified])
eberlm@61524
  2064
eberlm@61524
  2065
corollary setprod_shift_bounds_Suc_ivl:
eberlm@61524
  2066
  "setprod f {Suc m..<Suc n} = setprod (%i. f(Suc i)){m..<n}"
eberlm@61524
  2067
by (simp add:setprod_shift_bounds_nat_ivl[where k="Suc 0", simplified])
eberlm@61524
  2068
eberlm@61524
  2069
lemma setprod_lessThan_Suc: "setprod f {..<Suc n} = setprod f {..<n} * f n"
eberlm@61524
  2070
  by (simp add: lessThan_Suc mult.commute)
eberlm@61524
  2071
eberlm@63317
  2072
lemma setprod_lessThan_Suc_shift:"(\<Prod>i<Suc n. f i) = f 0 * (\<Prod>i<n. f (Suc i))"
eberlm@63317
  2073
  by (induction n) (simp_all add: lessThan_Suc mult_ac)
eberlm@63317
  2074
eberlm@61524
  2075
lemma setprod_atLeastLessThan_Suc: "a \<le> b \<Longrightarrow> setprod f {a..<Suc b} = setprod f {a..<b} * f b"
eberlm@61524
  2076
  by (simp add: atLeastLessThanSuc mult.commute)
eberlm@61524
  2077
eberlm@61524
  2078
lemma setprod_nat_ivl_Suc':
eberlm@61524
  2079
  assumes "m \<le> Suc n"
eberlm@61524
  2080
  shows   "setprod f {m..Suc n} = f (Suc n) * setprod f {m..n}"
eberlm@61524
  2081
proof -
eberlm@61524
  2082
  from assms have "{m..Suc n} = insert (Suc n) {m..n}" by auto
eberlm@61524
  2083
  also have "setprod f \<dots> = f (Suc n) * setprod f {m..n}" by simp
eberlm@61524
  2084
  finally show ?thesis .
eberlm@61524
  2085
qed
eberlm@61524
  2086
eberlm@62128
  2087
eberlm@62128
  2088
subsection \<open>Efficient folding over intervals\<close>
eberlm@62128
  2089
eberlm@62128
  2090
function fold_atLeastAtMost_nat where
eberlm@62128
  2091
  [simp del]: "fold_atLeastAtMost_nat f a (b::nat) acc =
eberlm@62128
  2092
                 (if a > b then acc else fold_atLeastAtMost_nat f (a+1) b (f a acc))"
eberlm@62128
  2093
by pat_completeness auto
eberlm@62128
  2094
termination by (relation "measure (\<lambda>(_,a,b,_). Suc b - a)") auto
eberlm@62128
  2095
eberlm@62128
  2096
lemma fold_atLeastAtMost_nat:
eberlm@62128
  2097
  assumes "comp_fun_commute f"
eberlm@62128
  2098
  shows   "fold_atLeastAtMost_nat f a b acc = Finite_Set.fold f acc {a..b}"
eberlm@62128
  2099
using assms
eberlm@62128
  2100
proof (induction f a b acc rule: fold_atLeastAtMost_nat.induct, goal_cases)
eberlm@62128
  2101
  case (1 f a b acc)
eberlm@62128
  2102
  interpret comp_fun_commute f by fact
eberlm@62128
  2103
  show ?case
eberlm@62128
  2104
  proof (cases "a > b")
eberlm@62128
  2105
    case True
eberlm@62128
  2106
    thus ?thesis by (subst fold_atLeastAtMost_nat.simps) auto
eberlm@62128
  2107
  next
eberlm@62128
  2108
    case False
eberlm@62128
  2109
    with 1 show ?thesis
eberlm@62128
  2110
      by (subst fold_atLeastAtMost_nat.simps)
eberlm@62128
  2111
         (auto simp: atLeastAtMost_insertL[symmetric] fold_fun_left_comm)
eberlm@62128
  2112
  qed
eberlm@62128
  2113
qed
eberlm@62128
  2114
eberlm@62128
  2115
lemma setsum_atLeastAtMost_code:
eberlm@62128
  2116
  "setsum f {a..b} = fold_atLeastAtMost_nat (\<lambda>a acc. f a + acc) a b 0"
eberlm@62128
  2117
proof -
eberlm@62128
  2118
  have "comp_fun_commute (\<lambda>a. op + (f a))"
eberlm@62128
  2119
    by unfold_locales (auto simp: o_def add_ac)
eberlm@62128
  2120
  thus ?thesis
eberlm@62128
  2121
    by (simp add: setsum.eq_fold fold_atLeastAtMost_nat o_def)
eberlm@62128
  2122
qed
eberlm@62128
  2123
eberlm@62128
  2124
lemma setprod_atLeastAtMost_code:
eberlm@62128
  2125
  "setprod f {a..b} = fold_atLeastAtMost_nat (\<lambda>a acc. f a * acc) a b 1"
eberlm@62128
  2126
proof -
eberlm@62128
  2127
  have "comp_fun_commute (\<lambda>a. op * (f a))"
eberlm@62128
  2128
    by unfold_locales (auto simp: o_def mult_ac)
eberlm@62128
  2129
  thus ?thesis
eberlm@62128
  2130
    by (simp add: setprod.eq_fold fold_atLeastAtMost_nat o_def)
eberlm@62128
  2131
qed
eberlm@62128
  2132
eberlm@62128
  2133
(* TODO: Add support for more kinds of intervals here *)
eberlm@62128
  2134
haftmann@63417
  2135
haftmann@63417
  2136
subsection \<open>Transfer setup\<close>
haftmann@63417
  2137
haftmann@63417
  2138
lemma transfer_nat_int_set_functions:
haftmann@63417
  2139
    "{..n} = nat ` {0..int n}"
haftmann@63417
  2140
    "{m..n} = nat ` {int m..int n}"  (* need all variants of these! *)
haftmann@63417
  2141
  apply (auto simp add: image_def)
haftmann@63417
  2142
  apply (rule_tac x = "int x" in bexI)
haftmann@63417
  2143
  apply auto
haftmann@63417
  2144
  apply (rule_tac x = "int x" in bexI)
haftmann@63417
  2145
  apply auto
haftmann@63417
  2146
  done
haftmann@63417
  2147
haftmann@63417
  2148
lemma transfer_nat_int_set_function_closures:
haftmann@63417
  2149
    "x >= 0 \<Longrightarrow> nat_set {x..y}"
haftmann@63417
  2150
  by (simp add: nat_set_def)
haftmann@63417
  2151
haftmann@63417
  2152
declare transfer_morphism_nat_int[transfer add
haftmann@63417
  2153
  return: transfer_nat_int_set_functions
haftmann@63417
  2154
    transfer_nat_int_set_function_closures
haftmann@63417
  2155
]
haftmann@63417
  2156
haftmann@63417
  2157
lemma transfer_int_nat_set_functions:
haftmann@63417
  2158
    "is_nat m \<Longrightarrow> is_nat n \<Longrightarrow> {m..n} = int ` {nat m..nat n}"
haftmann@63417
  2159
  by (simp only: is_nat_def transfer_nat_int_set_functions
haftmann@63417
  2160
    transfer_nat_int_set_function_closures
haftmann@63417
  2161
    transfer_nat_int_set_return_embed nat_0_le
haftmann@63417
  2162
    cong: transfer_nat_int_set_cong)
haftmann@63417
  2163
haftmann@63417
  2164
lemma transfer_int_nat_set_function_closures:
haftmann@63417
  2165
    "is_nat x \<Longrightarrow> nat_set {x..y}"
haftmann@63417
  2166
  by (simp only: transfer_nat_int_set_function_closures is_nat_def)
haftmann@63417
  2167
haftmann@63417
  2168
declare transfer_morphism_int_nat[transfer add
haftmann@63417
  2169
  return: transfer_int_nat_set_functions
haftmann@63417
  2170
    transfer_int_nat_set_function_closures
haftmann@63417
  2171
]
haftmann@63417
  2172
nipkow@8924
  2173
end