# HG changeset patch
# User hoelzl
# Date 1384280935 -3600
# Node ID 7fb88ed6ff3c5a109f92332359bb89f7a20634b9
# Parent  eaf25431d4c427b680671afd5628b42bbf4dbb52
better support for enat and ereal conversions

diff -r eaf25431d4c4 -r 7fb88ed6ff3c src/HOL/Library/Extended_Nat.thy
--- a/src/HOL/Library/Extended_Nat.thy	Tue Nov 12 19:28:55 2013 +0100
+++ b/src/HOL/Library/Extended_Nat.thy	Tue Nov 12 19:28:55 2013 +0100
@@ -60,10 +60,10 @@
 lemmas enat2_cases = enat.exhaust[case_product enat.exhaust]
 lemmas enat3_cases = enat.exhaust[case_product enat.exhaust enat.exhaust]
 
-lemma not_infinity_eq [iff]: "(x \<noteq> \<infinity>) = (EX i. x = enat i)"
+lemma not_infinity_eq [iff]: "(x \<noteq> \<infinity>) = (\<exists>i. x = enat i)"
   by (cases x) auto
 
-lemma not_enat_eq [iff]: "(ALL y. x ~= enat y) = (x = \<infinity>)"
+lemma not_enat_eq [iff]: "(\<forall>y. x \<noteq> enat y) = (x = \<infinity>)"
   by (cases x) auto
 
 primrec the_enat :: "enat \<Rightarrow> nat"
@@ -94,6 +94,12 @@
 lemma enat_1 [code_post]: "enat 1 = 1"
   by (simp add: one_enat_def)
 
+lemma enat_0_iff: "enat x = 0 \<longleftrightarrow> x = 0" "0 = enat x \<longleftrightarrow> x = 0"
+  by (auto simp add: zero_enat_def)
+
+lemma enat_1_iff: "enat x = 1 \<longleftrightarrow> x = 1" "1 = enat x \<longleftrightarrow> x = 1"
+  by (auto simp add: one_enat_def)
+
 lemma one_eSuc: "1 = eSuc 0"
   by (simp add: zero_enat_def one_enat_def eSuc_def)
 
diff -r eaf25431d4c4 -r 7fb88ed6ff3c src/HOL/Library/Extended_Real.thy
--- a/src/HOL/Library/Extended_Real.thy	Tue Nov 12 19:28:55 2013 +0100
+++ b/src/HOL/Library/Extended_Real.thy	Tue Nov 12 19:28:55 2013 +0100
@@ -188,6 +188,11 @@
   "0 = ereal r \<longleftrightarrow> r = 0"
   unfolding zero_ereal_def by simp_all
 
+lemma ereal_eq_1[simp]:
+  "ereal r = 1 \<longleftrightarrow> r = 1"
+  "1 = ereal r \<longleftrightarrow> r = 1"
+  unfolding one_ereal_def by simp_all
+
 instance
 proof
   fix a b c :: ereal
@@ -288,9 +293,11 @@
 lemma ereal_less[simp]:
   "ereal r < 0 \<longleftrightarrow> (r < 0)"
   "0 < ereal r \<longleftrightarrow> (0 < r)"
+  "ereal r < 1 \<longleftrightarrow> (r < 1)"
+  "1 < ereal r \<longleftrightarrow> (1 < r)"
   "0 < (\<infinity>::ereal)"
   "-(\<infinity>::ereal) < 0"
-  by (simp_all add: zero_ereal_def)
+  by (simp_all add: zero_ereal_def one_ereal_def)
 
 lemma ereal_less_eq[simp]:
   "x \<le> (\<infinity>::ereal)"
@@ -298,7 +305,9 @@
   "ereal r \<le> ereal p \<longleftrightarrow> r \<le> p"
   "ereal r \<le> 0 \<longleftrightarrow> r \<le> 0"
   "0 \<le> ereal r \<longleftrightarrow> 0 \<le> r"
-  by (auto simp add: less_eq_ereal_def zero_ereal_def)
+  "ereal r \<le> 1 \<longleftrightarrow> r \<le> 1"
+  "1 \<le> ereal r \<longleftrightarrow> 1 \<le> r"
+  by (auto simp add: less_eq_ereal_def zero_ereal_def one_ereal_def)
 
 lemma ereal_infty_less_eq2:
   "a \<le> b \<Longrightarrow> a = \<infinity> \<Longrightarrow> b = (\<infinity>::ereal)"
@@ -458,6 +467,11 @@
   shows "\<bar>a\<bar> \<noteq> \<infinity> \<Longrightarrow> c < b \<Longrightarrow> a + c < a + b"
   by (cases rule: ereal2_cases[of b c]) auto
 
+lemma ereal_add_nonneg_eq_0_iff:
+  fixes a b :: ereal
+  shows "0 \<le> a \<Longrightarrow> 0 \<le> b \<Longrightarrow> a + b = 0 \<longleftrightarrow> a = 0 \<and> b = 0"
+  by (cases a b rule: ereal2_cases) auto
+
 lemma ereal_uminus_eq_reorder: "- a = b \<longleftrightarrow> a = (-b::ereal)"
   by auto
 
@@ -516,8 +530,8 @@
 
 lemma
   fixes f :: "nat \<Rightarrow> ereal"
-  shows incseq_uminus[simp]: "incseq (\<lambda>x. - f x) \<longleftrightarrow> decseq f"
-  and decseq_uminus[simp]: "decseq (\<lambda>x. - f x) \<longleftrightarrow> incseq f"
+  shows ereal_incseq_uminus[simp]: "incseq (\<lambda>x. - f x) \<longleftrightarrow> decseq f"
+    and ereal_decseq_uminus[simp]: "decseq (\<lambda>x. - f x) \<longleftrightarrow> incseq f"
   unfolding decseq_def incseq_def by auto
 
 lemma incseq_ereal: "incseq f \<Longrightarrow> incseq (\<lambda>x. ereal (f x))"
@@ -620,14 +634,6 @@
 lemma ereal_m1_less_0[simp]: "-(1::ereal) < 0"
   by (simp add: zero_ereal_def one_ereal_def)
 
-lemma ereal_zero_m1[simp]: "1 \<noteq> (0::ereal)"
-  by (simp add: zero_ereal_def one_ereal_def)
-
-lemma ereal_times_0[simp]:
-  fixes x :: ereal
-  shows "0 * x = 0"
-  by (cases x) (auto simp: zero_ereal_def)
-
 lemma ereal_times[simp]:
   "1 \<noteq> (\<infinity>::ereal)" "(\<infinity>::ereal) \<noteq> 1"
   "1 \<noteq> -(\<infinity>::ereal)" "-(\<infinity>::ereal) \<noteq> 1"
@@ -655,12 +661,12 @@
     (a = \<infinity> \<and> b < 0) \<or> (a < 0 \<and> b = \<infinity>) \<or> (a = -\<infinity> \<and> b > 0) \<or> (a > 0 \<and> b = -\<infinity>)"
   by (cases rule: ereal2_cases[of a b]) auto
 
+lemma ereal_abs_mult: "\<bar>x * y :: ereal\<bar> = \<bar>x\<bar> * \<bar>y\<bar>"
+  by (cases x y rule: ereal2_cases) (auto simp: abs_mult)
+
 lemma ereal_0_less_1[simp]: "0 < (1::ereal)"
   by (simp_all add: zero_ereal_def one_ereal_def)
 
-lemma ereal_zero_one[simp]: "0 \<noteq> (1::ereal)"
-  by (simp_all add: zero_ereal_def one_ereal_def)
-
 lemma ereal_mult_minus_left[simp]:
   fixes a b :: ereal
   shows "-a * b = - (a * b)"
@@ -952,7 +958,7 @@
       by simp
   }
   then show ?thesis
-    by (auto intro!: image_eqI)
+    by force
 qed
 
 lemma ereal_uminus_greaterThan[simp]: "uminus ` {(a::ereal)<..} = {..<-a}"
@@ -1267,7 +1273,7 @@
   shows "z / x \<le> z / y"
   using assms
   by (cases x y z rule: ereal3_cases)
-    (auto intro: divide_left_mono simp: field_simps sign_simps split: split_if_asm)
+     (auto intro: divide_left_mono simp: field_simps zero_less_mult_iff mult_less_0_iff split: split_if_asm)
 
 lemma ereal_divide_zero_left[simp]:
   fixes a :: ereal
@@ -1277,7 +1283,7 @@
 lemma ereal_times_divide_eq_left[simp]:
   fixes a b c :: ereal
   shows "b / c * a = b * a / c"
-  by (cases a b c rule: ereal3_cases) (auto simp: field_simps sign_simps)
+  by (cases a b c rule: ereal3_cases) (auto simp: field_simps zero_less_mult_iff mult_less_0_iff)
 
 
 subsection "Complete lattice"
@@ -1380,7 +1386,7 @@
 instance ereal :: linear_continuum
 proof
   show "\<exists>a b::ereal. a \<noteq> b"
-    using ereal_zero_one by blast
+    using zero_neq_one by blast
 qed
 
 lemma ereal_Sup_uminus_image_eq: "Sup (uminus ` S::ereal set) = - Inf S"
@@ -1394,6 +1400,18 @@
 lemma ereal_Inf_uminus_image_eq: "Inf (uminus ` S::ereal set) = - Sup S"
   using ereal_Sup_uminus_image_eq[of "uminus ` S"] by simp
 
+lemma ereal_SUP_not_infty:
+  fixes f :: "_ \<Rightarrow> ereal"
+  shows "A \<noteq> {} \<Longrightarrow> l \<noteq> -\<infinity> \<Longrightarrow> u \<noteq> \<infinity> \<Longrightarrow> \<forall>a\<in>A. l \<le> f a \<and> f a \<le> u \<Longrightarrow> \<bar>SUPR A f\<bar> \<noteq> \<infinity>"
+  using SUP_upper2[of _ A l f] SUP_least[of A f u]
+  by (cases "SUPR A f") auto
+
+lemma ereal_INF_not_infty:
+  fixes f :: "_ \<Rightarrow> ereal"
+  shows "A \<noteq> {} \<Longrightarrow> l \<noteq> -\<infinity> \<Longrightarrow> u \<noteq> \<infinity> \<Longrightarrow> \<forall>a\<in>A. l \<le> f a \<and> f a \<le> u \<Longrightarrow> \<bar>INFI A f\<bar> \<noteq> \<infinity>"
+  using INF_lower2[of _ A f u] INF_greatest[of A l f]
+  by (cases "INFI A f") auto
+
 lemma ereal_SUPR_uminus:
   fixes f :: "'a \<Rightarrow> ereal"
   shows "(SUP i : R. -(f i)) = -(INF i : R. f i)"
@@ -1712,8 +1730,7 @@
   next
     case False
     have "\<exists>x\<in>A. 0 \<le> x"
-      by (metis Infty_neq_0 PInf complete_lattice_class.Sup_least
-          ereal_infty_less_eq2 linorder_linear)
+      by (metis Infty_neq_0(2) PInf complete_lattice_class.Sup_least ereal_infty_less_eq2(1) linorder_linear)
     then obtain x where "x \<in> A" and "0 \<le> x"
       by auto
     have "\<forall>n::nat. \<exists>f. f \<in> A \<and> x + ereal (real n) \<le> f"
@@ -1845,7 +1862,6 @@
   finally show ?thesis .
 qed
 
-
 subsection "Relation to @{typ enat}"
 
 definition "ereal_of_enat n = (case n of enat n \<Rightarrow> ereal (real n) | \<infinity> \<Rightarrow> \<infinity>)"
@@ -2413,12 +2429,6 @@
   (is "?lhs \<longleftrightarrow> ?rhs")
   unfolding le_Liminf_iff eventually_sequentially ..
 
-lemma
-  fixes X :: "nat \<Rightarrow> ereal"
-  shows ereal_incseq_uminus[simp]: "incseq (\<lambda>i. - X i) = decseq X"
-    and ereal_decseq_uminus[simp]: "decseq (\<lambda>i. - X i) = incseq X"
-  unfolding incseq_def decseq_def by auto
-
 
 subsubsection {* Tests for code generator *}