# HG changeset patch
# User huffman
# Date 1159386278 -7200
# Node ID 5a103b43da5ad7f0e1ac70589628e7352a592096
# Parent  8df08902da6ff17234da93fe459f15cf87eb9a72
reorganized HNatInfinite proofs; simplified and renamed some lemmas

diff -r 8df08902da6f -r 5a103b43da5a src/HOL/Hyperreal/HTranscendental.thy
--- a/src/HOL/Hyperreal/HTranscendental.thy	Wed Sep 27 21:33:13 2006 +0200
+++ b/src/HOL/Hyperreal/HTranscendental.thy	Wed Sep 27 21:44:38 2006 +0200
@@ -499,7 +499,7 @@
      "N \<in> HNatInfinite  
       ==> hypreal_of_real a =  
           hypreal_of_hypnat N * (inverse(hypreal_of_hypnat N) * hypreal_of_real a)"
-by (simp add: mult_assoc [symmetric] HNatInfinite_not_eq_zero)
+by (simp add: mult_assoc [symmetric] zero_less_HNatInfinite)
 
 lemma STAR_sin_Infinitesimal_divide:
      "[|x \<in> Infinitesimal; x \<noteq> 0 |] ==> ( *f* sin) x/x @= 1"
@@ -515,7 +515,7 @@
      "n \<in> HNatInfinite  
       ==> ( *f* sin) (inverse (hypreal_of_hypnat n))/(inverse (hypreal_of_hypnat n)) @= 1"
 apply (rule STAR_sin_Infinitesimal_divide)
-apply (auto simp add: HNatInfinite_not_eq_zero)
+apply (auto simp add: zero_less_HNatInfinite)
 done
 
 lemma STAR_sin_inverse_HNatInfinite:
@@ -534,7 +534,7 @@
 
 lemma pi_divide_HNatInfinite_not_zero [simp]:
      "N \<in> HNatInfinite ==> hypreal_of_real pi/(hypreal_of_hypnat N) \<noteq> 0"
-by (simp add: HNatInfinite_not_eq_zero)
+by (simp add: zero_less_HNatInfinite)
 
 lemma STAR_sin_pi_divide_HNatInfinite_approx_pi:
      "n \<in> HNatInfinite  
diff -r 8df08902da6f -r 5a103b43da5a src/HOL/Hyperreal/HyperNat.thy
--- a/src/HOL/Hyperreal/HyperNat.thy	Wed Sep 27 21:33:13 2006 +0200
+++ b/src/HOL/Hyperreal/HyperNat.thy	Wed Sep 27 21:44:38 2006 +0200
@@ -85,6 +85,9 @@
 lemma hypnat_le0 [iff]: "!!n. (0::hypnat) \<le> n"
 by transfer (rule le0)
 
+lemma hypnat_le_add1 [simp]: "!!x n. (x::hypnat) \<le> x + n"
+by transfer (rule le_add1)
+
 lemma hypnat_add_self_le [simp]: "!!x n. (x::hypnat) \<le> n + x"
 by transfer (rule le_add2)
 
@@ -123,15 +126,24 @@
 
 subsection{*Properties of the set of embedded natural numbers*}
 
-lemma hypnat_of_nat_def: "hypnat_of_nat m == of_nat m"
-by (transfer, simp)
+lemma of_nat_eq_star_of [simp]: "of_nat = star_of"
+proof
+  fix n :: nat
+  show "of_nat n = star_of n" by transfer simp
+qed
+
+lemma Nats_eq_Standard: "(Nats :: nat star set) = Standard"
+by (auto simp add: Nats_def Standard_def)
+
+lemma hypnat_of_nat_mem_Nats [simp]: "hypnat_of_nat n \<in> Nats"
+by (simp add: Nats_eq_Standard)
 
 lemma hypnat_of_nat_one [simp]: "hypnat_of_nat (Suc 0) = (1::hypnat)"
-by simp
+by transfer simp
 
 lemma hypnat_of_nat_Suc [simp]:
      "hypnat_of_nat (Suc n) = hypnat_of_nat n + (1::hypnat)"
-by (simp add: hypnat_of_nat_def)
+by transfer simp
 
 lemma of_nat_eq_add [rule_format]:
      "\<forall>d::hypnat. of_nat m = of_nat n + d --> d \<in> range of_nat"
@@ -142,8 +154,100 @@
 done
 
 lemma Nats_diff [simp]: "[|a \<in> Nats; b \<in> Nats|] ==> (a-b :: hypnat) \<in> Nats"
-by (auto simp add: of_nat_eq_add Nats_def split: hypnat_diff_split)
+by (simp add: Nats_eq_Standard)
+
+
+subsection{*Infinite Hypernatural Numbers -- @{term HNatInfinite}*}
+
+definition
+  (* the set of infinite hypernatural numbers *)
+  HNatInfinite :: "hypnat set"
+  "HNatInfinite = {n. n \<notin> Nats}"
+
+lemma Nats_not_HNatInfinite_iff: "(x \<in> Nats) = (x \<notin> HNatInfinite)"
+by (simp add: HNatInfinite_def)
+
+lemma HNatInfinite_not_Nats_iff: "(x \<in> HNatInfinite) = (x \<notin> Nats)"
+by (simp add: HNatInfinite_def)
+
+lemma star_of_neq_HNatInfinite: "N \<in> HNatInfinite \<Longrightarrow> star_of n \<noteq> N"
+by (auto simp add: HNatInfinite_def Nats_eq_Standard)
+
+lemma star_of_Suc_lessI:
+  "\<And>N. \<lbrakk>star_of n < N; star_of (Suc n) \<noteq> N\<rbrakk> \<Longrightarrow> star_of (Suc n) < N"
+by transfer (rule Suc_lessI)
+
+lemma star_of_less_HNatInfinite:
+  assumes N: "N \<in> HNatInfinite"
+  shows "star_of n < N"
+proof (induct n)
+  case 0
+  from N have "star_of 0 \<noteq> N" by (rule star_of_neq_HNatInfinite)
+  thus "star_of 0 < N" by simp
+next
+  case (Suc n)
+  from N have "star_of (Suc n) \<noteq> N" by (rule star_of_neq_HNatInfinite)
+  with Suc show "star_of (Suc n) < N" by (rule star_of_Suc_lessI)
+qed
+
+lemma star_of_le_HNatInfinite: "N \<in> HNatInfinite \<Longrightarrow> star_of n \<le> N"
+by (rule star_of_less_HNatInfinite [THEN order_less_imp_le])
+
+subsubsection {* Closure Rules *}
+
+lemma Nats_less_HNatInfinite: "\<lbrakk>x \<in> Nats; y \<in> HNatInfinite\<rbrakk> \<Longrightarrow> x < y"
+by (auto simp add: Nats_def star_of_less_HNatInfinite)
+
+lemma Nats_le_HNatInfinite: "\<lbrakk>x \<in> Nats; y \<in> HNatInfinite\<rbrakk> \<Longrightarrow> x \<le> y"
+by (rule Nats_less_HNatInfinite [THEN order_less_imp_le])
 
+lemma zero_less_HNatInfinite: "x \<in> HNatInfinite \<Longrightarrow> 0 < x"
+by (simp add: Nats_less_HNatInfinite)
+
+lemma one_less_HNatInfinite: "x \<in> HNatInfinite \<Longrightarrow> 1 < x"
+by (simp add: Nats_less_HNatInfinite)
+
+lemma one_le_HNatInfinite: "x \<in> HNatInfinite \<Longrightarrow> 1 \<le> x"
+by (simp add: Nats_le_HNatInfinite)
+
+lemma zero_not_mem_HNatInfinite [simp]: "0 \<notin> HNatInfinite"
+by (simp add: HNatInfinite_def)
+
+lemma Nats_downward_closed:
+  "\<lbrakk>x \<in> Nats; (y::hypnat) \<le> x\<rbrakk> \<Longrightarrow> y \<in> Nats"
+apply (simp only: linorder_not_less [symmetric])
+apply (erule contrapos_np)
+apply (drule HNatInfinite_not_Nats_iff [THEN iffD2])
+apply (erule (1) Nats_less_HNatInfinite)
+done
+
+lemma HNatInfinite_upward_closed:
+  "\<lbrakk>x \<in> HNatInfinite; x \<le> y\<rbrakk> \<Longrightarrow> y \<in> HNatInfinite"
+apply (simp only: HNatInfinite_not_Nats_iff)
+apply (erule contrapos_nn)
+apply (erule (1) Nats_downward_closed)
+done
+
+lemma HNatInfinite_add: "x \<in> HNatInfinite \<Longrightarrow> x + y \<in> HNatInfinite"
+apply (erule HNatInfinite_upward_closed)
+apply (rule hypnat_le_add1)
+done
+
+lemma HNatInfinite_add_one: "x \<in> HNatInfinite \<Longrightarrow> x + 1 \<in> HNatInfinite"
+by (rule HNatInfinite_add)
+
+lemma HNatInfinite_diff:
+  "\<lbrakk>x \<in> HNatInfinite; y \<in> Nats\<rbrakk> \<Longrightarrow> x - y \<in> HNatInfinite"
+apply (frule (1) Nats_le_HNatInfinite)
+apply (simp only: HNatInfinite_not_Nats_iff)
+apply (erule contrapos_nn)
+apply (drule (1) Nats_add, simp)
+done
+
+lemma HNatInfinite_is_Suc: "x \<in> HNatInfinite ==> \<exists>y. x = y + (1::hypnat)"
+apply (rule_tac x = "x - (1::hypnat) " in exI)
+apply (simp add: Nats_le_HNatInfinite)
+done
 
 
 subsection{*Existence of an infinite hypernatural number*}
@@ -153,9 +257,17 @@
   whn :: hypnat
   hypnat_omega_def: "whn = star_n (%n::nat. n)"
 
-text{*Existence of infinite number not corresponding to any natural number
-follows because member @{term FreeUltrafilterNat} is not finite.
-See @{text HyperDef.thy} for similar argument.*}
+lemma hypnat_of_nat_neq_whn: "hypnat_of_nat n \<noteq> whn"
+by (simp add: hypnat_omega_def star_of_def star_n_eq_iff FUFNat.finite)
+
+lemma whn_neq_hypnat_of_nat: "whn \<noteq> hypnat_of_nat n"
+by (simp add: hypnat_omega_def star_of_def star_n_eq_iff FUFNat.finite)
+
+lemma whn_not_Nats [simp]: "whn \<notin> Nats"
+by (simp add: Nats_def image_def whn_neq_hypnat_of_nat)
+
+lemma HNatInfinite_whn [simp]: "whn \<in> HNatInfinite"
+by (simp add: HNatInfinite_def)
 
 text{* Example of an hypersequence (i.e. an extended standard sequence)
    whose term with an hypernatural suffix is an infinitesimal i.e.
@@ -171,7 +283,7 @@
 lemma lemma_unbounded_set [simp]: "{n::nat. m < n} \<in> FreeUltrafilterNat"
 apply (insert finite_atMost [of m]) 
 apply (simp add: atMost_def) 
-apply (drule FreeUltrafilterNat_finite) 
+apply (drule FreeUltrafilterNat_finite)
 apply (drule FreeUltrafilterNat_Compl_mem, ultra)
 done
 
@@ -183,46 +295,25 @@
 by (simp add: star_of_def)
 
 lemma SHNat_eq: "Nats = {n. \<exists>N. n = hypnat_of_nat N}"
-by (force simp add: hypnat_of_nat_def Nats_def) 
+by (simp add: Nats_def image_def)
 
-lemma hypnat_omega_gt_SHNat:
-     "n \<in> Nats ==> n < whn"
-by (auto simp add: hypnat_of_nat_eq star_n_less hypnat_omega_def SHNat_eq)
+lemma Nats_less_whn: "n \<in> Nats \<Longrightarrow> n < whn"
+by (simp add: Nats_less_HNatInfinite)
 
-(* Infinite hypernatural not in embedded Nats *)
-lemma SHNAT_omega_not_mem [simp]: "whn \<notin> Nats"
-by (blast dest: hypnat_omega_gt_SHNat)
+lemma Nats_le_whn: "n \<in> Nats \<Longrightarrow> n \<le> whn"
+by (simp add: Nats_le_HNatInfinite)
 
 lemma hypnat_of_nat_less_whn [simp]: "hypnat_of_nat n < whn"
-apply (insert hypnat_omega_gt_SHNat [of "hypnat_of_nat n"])
-apply (simp add: hypnat_of_nat_def) 
-done
+by (simp add: Nats_less_whn)
 
 lemma hypnat_of_nat_le_whn [simp]: "hypnat_of_nat n \<le> whn"
-by (rule hypnat_of_nat_less_whn [THEN order_less_imp_le])
+by (simp add: Nats_le_whn)
 
 lemma hypnat_zero_less_hypnat_omega [simp]: "0 < whn"
-by (simp add: hypnat_omega_gt_SHNat)
-
-lemma hypnat_one_less_hypnat_omega [simp]: "(1::hypnat) < whn"
-by (simp add: hypnat_omega_gt_SHNat)
-
-
-subsection{*Infinite Hypernatural Numbers -- @{term HNatInfinite}*}
+by (simp add: Nats_less_whn)
 
-definition
-  (* the set of infinite hypernatural numbers *)
-  HNatInfinite :: "hypnat set"
-  "HNatInfinite = {n. n \<notin> Nats}"
-
-lemma HNatInfinite_whn [simp]: "whn \<in> HNatInfinite"
-by (simp add: HNatInfinite_def)
-
-lemma Nats_not_HNatInfinite_iff: "(x \<in> Nats) = (x \<notin> HNatInfinite)"
-by (simp add: HNatInfinite_def)
-
-lemma HNatInfinite_not_Nats_iff: "(x \<in> HNatInfinite) = (x \<notin> Nats)"
-by (simp add: HNatInfinite_def)
+lemma hypnat_one_less_hypnat_omega [simp]: "1 < whn"
+by (simp add: Nats_less_whn)
 
 
 subsubsection{*Alternative characterization of the set of infinite hypernaturals*}
@@ -243,7 +334,7 @@
 apply (auto simp add: HNatInfinite_def SHNat_eq hypnat_of_nat_eq)
 apply (rule_tac x = x in star_cases)
 apply (auto elim: HNatInfinite_FreeUltrafilterNat_lemma 
-            simp add: star_n_less FreeUltrafilterNat_Compl_iff1 
+            simp add: star_n_less FreeUltrafilterNat_Compl_iff1
                       star_n_eq_iff Collect_neg_eq [symmetric])
 done
 
@@ -267,64 +358,6 @@
 by (rule iffI [OF HNatInfinite_FreeUltrafilterNat 
                  FreeUltrafilterNat_HNatInfinite])
 
-lemma HNatInfinite_gt_one [simp]: "x \<in> HNatInfinite ==> (1::hypnat) < x"
-by (auto simp add: HNatInfinite_iff)
-
-lemma zero_not_mem_HNatInfinite [simp]: "0 \<notin> HNatInfinite"
-apply (auto simp add: HNatInfinite_iff)
-apply (drule_tac a = " (1::hypnat) " in equals0D)
-apply simp
-done
-
-lemma HNatInfinite_not_eq_zero: "x \<in> HNatInfinite ==> 0 < x"
-apply (drule HNatInfinite_gt_one) 
-apply (auto simp add: order_less_trans [OF zero_less_one])
-done
-
-lemma HNatInfinite_ge_one [simp]: "x \<in> HNatInfinite ==> (1::hypnat) \<le> x"
-by (blast intro: order_less_imp_le HNatInfinite_gt_one)
-
-
-subsubsection{*Closure Rules*}
-
-lemma HNatInfinite_add:
-     "[| x \<in> HNatInfinite; y \<in> HNatInfinite |] ==> x + y \<in> HNatInfinite"
-apply (auto simp add: HNatInfinite_iff)
-apply (drule bspec, assumption)
-apply (drule bspec [OF _ Nats_0])
-apply (drule add_strict_mono, assumption, simp)
-done
-
-lemma HNatInfinite_SHNat_add:
-     "[| x \<in> HNatInfinite; y \<in> Nats |] ==> x + y \<in> HNatInfinite"
-apply (auto simp add: HNatInfinite_not_Nats_iff) 
-apply (drule_tac a = "x + y" in Nats_diff, auto) 
-done
-
-lemma HNatInfinite_Nats_imp_less: "[| x \<in> HNatInfinite; y \<in> Nats |] ==> y < x"
-by (simp add: HNatInfinite_iff) 
-
-lemma HNatInfinite_SHNat_diff:
-  assumes x: "x \<in> HNatInfinite" and y: "y \<in> Nats" 
-  shows "x - y \<in> HNatInfinite"
-proof -
-  have "y < x" by (simp add: HNatInfinite_Nats_imp_less prems)
-  hence "x - y + y = x" by (simp add: order_less_imp_le)
-  with x show ?thesis
-    by (force simp add: HNatInfinite_not_Nats_iff 
-              dest: Nats_add [of "x-y", OF _ y]) 
-qed
-
-lemma HNatInfinite_add_one:
-     "x \<in> HNatInfinite ==> x + (1::hypnat) \<in> HNatInfinite"
-by (auto intro: HNatInfinite_SHNat_add)
-
-lemma HNatInfinite_is_Suc: "x \<in> HNatInfinite ==> \<exists>y. x = y + (1::hypnat)"
-apply (rule_tac x = "x - (1::hypnat) " in exI)
-apply auto
-done
-
-
 subsection{*Embedding of the Hypernaturals into the Hyperreals*}
 text{*Obtained using the nonstandard extension of the naturals*}
 
diff -r 8df08902da6f -r 5a103b43da5a src/HOL/Hyperreal/NatStar.thy
--- a/src/HOL/Hyperreal/NatStar.thy	Wed Sep 27 21:33:13 2006 +0200
+++ b/src/HOL/Hyperreal/NatStar.thy	Wed Sep 27 21:44:38 2006 +0200
@@ -122,7 +122,7 @@
    ==> ( *f* (%x::nat. inverse(real x))) N = inverse(hypreal_of_hypnat N)"
 apply (rule_tac f1 = inverse in starfun_o2 [THEN subst])
 apply (subgoal_tac "hypreal_of_hypnat N ~= 0")
-apply (simp_all add: HNatInfinite_not_eq_zero starfunNat_real_of_nat starfun_inverse_inverse)
+apply (simp_all add: zero_less_HNatInfinite starfunNat_real_of_nat starfun_inverse_inverse)
 done
 
 text{*Internal functions - some redundancy with *f* now*}
@@ -179,7 +179,7 @@
      "N \<in> HNatInfinite ==> ( *f* (%x. inverse (real x))) N \<in> Infinitesimal"
 apply (rule_tac f1 = inverse in starfun_o2 [THEN subst])
 apply (subgoal_tac "hypreal_of_hypnat N ~= 0")
-apply (simp_all add: HNatInfinite_not_eq_zero starfunNat_real_of_nat)
+apply (simp_all add: zero_less_HNatInfinite starfunNat_real_of_nat)
 done
 
 
diff -r 8df08902da6f -r 5a103b43da5a src/HOL/Hyperreal/SEQ.thy
--- a/src/HOL/Hyperreal/SEQ.thy	Wed Sep 27 21:33:13 2006 +0200
+++ b/src/HOL/Hyperreal/SEQ.thy	Wed Sep 27 21:44:38 2006 +0200
@@ -991,7 +991,7 @@
 lemma NSLIMSEQ_Suc: "f ----NS> l ==> (%n. f(Suc n)) ----NS> l"
 apply (unfold NSLIMSEQ_def, safe)
 apply (drule_tac x="N + 1" in bspec)
-apply (erule Nats_1 [THEN [2] HNatInfinite_SHNat_add])
+apply (erule HNatInfinite_add)
 apply (simp add: starfun_shift_one)
 done
 
@@ -1002,8 +1002,8 @@
 lemma NSLIMSEQ_imp_Suc: "(%n. f(Suc n)) ----NS> l ==> f ----NS> l"
 apply (unfold NSLIMSEQ_def, safe)
 apply (drule_tac x="N - 1" in bspec) 
-apply (erule Nats_1 [THEN [2] HNatInfinite_SHNat_diff])
-apply (simp add: starfun_shift_one)
+apply (erule Nats_1 [THEN [2] HNatInfinite_diff])
+apply (simp add: starfun_shift_one one_le_HNatInfinite)
 done
 
 lemma LIMSEQ_imp_Suc: "(%n. f(Suc n)) ----> l ==> f ----> l"