# HG changeset patch
# User oheimb
# Date 991321560 -7200
# Node ID c5c403d30c77d96c1652e860ed3bdbbf8d049036
# Parent  4c55b020d6ee3ff5ad7a52dd6148ac6fbc9f74b3
added Library/Nat_Infinity.thy and Library/Continuity.thy

diff -r 4c55b020d6ee -r c5c403d30c77 src/HOL/Library/Continuity.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Continuity.thy	Thu May 31 17:06:00 2001 +0200
@@ -0,0 +1,219 @@
+(*  Title:      HOL/Library/Continuity.thy
+    ID:         $$
+    Author: 	David von Oheimb, TU Muenchen
+    License:    GPL (GNU GENERAL PUBLIC LICENSE)
+
+*)
+
+header {*
+  \title{Continuity and interations (of set transformers)}
+  \author{David von Oheimb}
+*}
+
+theory Continuity = Relation_Power:
+
+
+subsection "Chains"
+
+constdefs
+  up_chain      :: "(nat => 'a set) => bool"
+ "up_chain F      == !i. F i <= F (Suc i)"
+
+lemma up_chainI: "(!!i. F i <= F (Suc i)) ==> up_chain F"
+by (simp add: up_chain_def);
+
+lemma up_chainD: "up_chain F ==> F i <= F (Suc i)"
+by (simp add: up_chain_def);
+
+lemma up_chain_less_mono [rule_format]: "up_chain F ==> x < y --> F x <= F y"
+apply (induct_tac y)
+apply (blast dest: up_chainD elim: less_SucE)+
+done
+
+lemma up_chain_mono: "up_chain F ==> x <= y ==> F x <= F y"
+apply (drule le_imp_less_or_eq)
+apply (blast dest: up_chain_less_mono)
+done
+
+
+constdefs
+  down_chain      :: "(nat => 'a set) => bool"
+ "down_chain F == !i. F (Suc i) <= F i"
+
+lemma down_chainI: "(!!i. F (Suc i) <= F i) ==> down_chain F"
+by (simp add: down_chain_def);
+
+lemma down_chainD: "down_chain F ==> F (Suc i) <= F i"
+by (simp add: down_chain_def);
+
+lemma down_chain_less_mono[rule_format]: "down_chain F ==> x < y --> F y <= F x"
+apply (induct_tac y)
+apply (blast dest: down_chainD elim: less_SucE)+
+done
+
+lemma down_chain_mono: "down_chain F ==> x <= y ==> F y <= F x"
+apply (drule le_imp_less_or_eq)
+apply (blast dest: down_chain_less_mono)
+done
+
+
+subsection "Continuity"
+
+constdefs
+  up_cont :: "('a set => 'a set) => bool"
+ "up_cont f == !F. up_chain F --> f (Union (range F)) = Union (f`(range F))"
+
+lemma up_contI: 
+ "(!!F. up_chain F ==> f (Union (range F)) = Union (f`(range F))) ==> up_cont f"
+apply (unfold up_cont_def)
+by blast
+
+lemma up_contD: 
+  "[| up_cont f; up_chain F |] ==> f (Union (range F)) = Union (f`(range F))"
+apply (unfold up_cont_def)
+by auto
+
+
+lemma up_cont_mono: "up_cont f ==> mono f"
+apply (rule monoI)
+apply (drule_tac F = "%i. if i = 0 then A else B" in up_contD)
+apply  (rule up_chainI)
+apply  simp+
+apply (drule Un_absorb1)
+apply auto
+done
+
+
+constdefs
+  down_cont :: "('a set => 'a set) => bool"
+ "down_cont f == !F. down_chain F --> f (Inter (range F)) = Inter (f`(range F))"
+
+lemma down_contI: 
+ "(!!F. down_chain F ==> f (Inter (range F)) = Inter (f`(range F))) ==> 
+  down_cont f"
+apply (unfold down_cont_def)
+by blast
+
+lemma down_contD: "[| down_cont f; down_chain F |] ==> 
+  f (Inter (range F)) = Inter (f`(range F))"
+apply (unfold down_cont_def)
+by auto
+
+lemma down_cont_mono: "down_cont f ==> mono f"
+apply (rule monoI)
+apply (drule_tac F = "%i. if i = 0 then B else A" in down_contD)
+apply  (rule down_chainI)
+apply  simp+
+apply (drule Int_absorb1)
+apply auto
+done
+
+
+subsection "Iteration"
+
+constdefs
+
+  up_iterate :: "('a set => 'a set) => nat => 'a set"
+ "up_iterate f n == (f^n) {}"
+
+lemma up_iterate_0 [simp]: "up_iterate f 0 = {}"
+by (simp add: up_iterate_def)
+
+lemma up_iterate_Suc [simp]: 
+  "up_iterate f (Suc i) = f (up_iterate f i)"
+by (simp add: up_iterate_def)
+
+lemma up_iterate_chain: "mono F ==> up_chain (up_iterate F)"
+apply (rule up_chainI)
+apply (induct_tac i)
+apply simp+
+apply (erule (1) monoD)
+done
+
+lemma UNION_up_iterate_is_fp: 
+"up_cont F ==> F (UNION UNIV (up_iterate F)) = UNION UNIV (up_iterate F)"
+apply (frule up_cont_mono [THEN up_iterate_chain])
+apply (drule (1) up_contD)
+apply simp
+apply (auto simp del: up_iterate_Suc simp add: up_iterate_Suc [symmetric])
+apply (case_tac "xa")
+apply auto
+done
+
+lemma UNION_up_iterate_lowerbound: 
+"[| mono F; F P = P |] ==> UNION UNIV (up_iterate F) <= P"
+apply (subgoal_tac "(!!i. up_iterate F i <= P)")
+apply  fast
+apply (induct_tac "i")
+prefer 2 apply (drule (1) monoD)
+apply auto
+done
+
+lemma UNION_up_iterate_is_lfp: 
+  "up_cont F ==> lfp F = UNION UNIV (up_iterate F)"
+apply (rule set_eq_subset [THEN iffD2])
+apply (rule conjI)
+prefer 2
+apply  (drule up_cont_mono)
+apply  (rule UNION_up_iterate_lowerbound)
+apply   assumption
+apply  (erule lfp_unfold [symmetric])
+apply (rule lfp_lowerbound)
+apply (rule set_eq_subset [THEN iffD1, THEN conjunct2])
+apply (erule UNION_up_iterate_is_fp [symmetric])
+done
+
+
+constdefs
+
+  down_iterate :: "('a set => 'a set) => nat => 'a set"
+ "down_iterate f n == (f^n) UNIV"
+
+lemma down_iterate_0 [simp]: "down_iterate f 0 = UNIV"
+by (simp add: down_iterate_def)
+
+lemma down_iterate_Suc [simp]: 
+  "down_iterate f (Suc i) = f (down_iterate f i)"
+by (simp add: down_iterate_def)
+
+lemma down_iterate_chain: "mono F ==> down_chain (down_iterate F)"
+apply (rule down_chainI)
+apply (induct_tac i)
+apply simp+
+apply (erule (1) monoD)
+done
+
+lemma INTER_down_iterate_is_fp: 
+"down_cont F ==> 
+ F (INTER UNIV (down_iterate F)) = INTER UNIV (down_iterate F)"
+apply (frule down_cont_mono [THEN down_iterate_chain])
+apply (drule (1) down_contD)
+apply simp
+apply (auto simp del: down_iterate_Suc simp add: down_iterate_Suc [symmetric])
+apply (case_tac "xa")
+apply auto
+done
+
+lemma INTER_down_iterate_upperbound: 
+"[| mono F; F P = P |] ==> P <= INTER UNIV (down_iterate F)"
+apply (subgoal_tac "(!!i. P <= down_iterate F i)")
+apply  fast
+apply (induct_tac "i")
+prefer 2 apply (drule (1) monoD)
+apply auto
+done
+
+lemma INTER_down_iterate_is_gfp: 
+  "down_cont F ==> gfp F = INTER UNIV (down_iterate F)"
+apply (rule set_eq_subset [THEN iffD2])
+apply (rule conjI)
+apply  (drule down_cont_mono)
+apply  (rule INTER_down_iterate_upperbound)
+apply   assumption
+apply  (erule gfp_unfold [symmetric])
+apply (rule gfp_upperbound)
+apply (rule set_eq_subset [THEN iffD1, THEN conjunct2])
+apply (erule INTER_down_iterate_is_fp)
+done
+
+end
diff -r 4c55b020d6ee -r c5c403d30c77 src/HOL/Library/Nat_Infinity.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Nat_Infinity.thy	Thu May 31 17:06:00 2001 +0200
@@ -0,0 +1,216 @@
+(*  Title: 	HOL/Library/Nat_Infinity.thy
+    ID:         $ $
+    Author: 	David von Oheimb, TU Muenchen
+    License:    GPL (GNU GENERAL PUBLIC LICENSE)
+
+*)
+
+header {*
+  \title{Natural numbers with infinity}
+  \author{David von Oheimb}
+*}
+
+theory Nat_Infinity = Datatype:
+
+subsection "Definitions"
+
+text {*
+ We extend the standard natural numbers by a special value indicating infinity.
+ This includes extending the ordering relations @{term "op <"} and 
+ @{term "op <="}.
+*}
+
+datatype inat = Fin nat | Infty
+
+instance inat :: ord ..
+instance inat :: zero ..
+
+consts
+
+  iSuc	:: "inat => inat"
+
+syntax (xsymbols)
+
+  Infty		:: inat					("\<infinity>")
+
+defs
+
+  iZero_def:	"0      == Fin 0"
+  iSuc_def:	"iSuc i == case i of Fin n  => Fin (Suc n) | \<infinity> => \<infinity>"
+  iless_def:	"m < n  == case m of Fin m1 => (case n of Fin n1 => m1 < n1 
+						             | \<infinity> => True)
+				   | \<infinity>  => False "
+  ile_def:	"(m::inat) <= n == \<not>(n<m)"
+
+lemmas inat_defs = iZero_def iSuc_def iless_def ile_def
+lemmas inat_splits = inat.split inat.split_asm
+
+
+text {* Below is a not quite complete set of theorems. Use
+@{text "apply(simp add:inat_defs split:inat_splits, arith?)"}
+to prove new theorems or solve arithmetic subgoals involving @{typ inat} 
+on the fly.
+*}
+
+subsection "Constructors"
+
+lemma Fin_0: "Fin 0 = 0"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Infty_ne_i0 [simp]: "\<infinity> \<noteq> 0"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma i0_ne_Infty [simp]: "0 \<noteq> \<infinity>"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iSuc_Fin [simp]: "iSuc (Fin n) = Fin (Suc n)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iSuc_Infty [simp]: "iSuc \<infinity> = \<infinity>"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iSuc_ne_0 [simp]: "iSuc n \<noteq> 0"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iSuc_inject [simp]: "(iSuc x = iSuc y) = (x = y)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+
+subsection "Ordering relations"
+
+lemma Infty_ilessE [elim!]: "\<infinity> < Fin m ==> R"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iless_linear: "m < n | m = n | n < (m::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iless_not_refl [simp]: "\<not> n < (n::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iless_trans: "i < j ==> j < k ==> i < (k::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iless_not_sym: "n < m ==> \<not> m < (n::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Fin_iless_mono [simp]: "(Fin n < Fin m) = (n < m)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Fin_iless_Infty [simp]: "Fin n < \<infinity>"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Infty_eq [simp]: "n < \<infinity> = (n \<noteq> \<infinity>)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma i0_eq [simp]: "((0::inat) < n) = (n \<noteq> 0)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma i0_iless_iSuc [simp]: "0 < iSuc n"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma not_ilessi0 [simp]: "\<not> n < (0::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Fin_iless: "n < Fin m ==> \<exists>k. n = Fin k"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iSuc_mono [simp]: "iSuc n < iSuc m = (n < m)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+
+(* ----------------------------------------------------------------------- *)
+
+lemma ile_def2: "m <= n = (m < n | m = (n::inat))"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma ile_refl [simp]: "n <= (n::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma ile_trans: "i <= j ==> j <= k ==> i <= (k::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma ile_iless_trans: "i <= j ==> j < k ==> i < (k::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iless_ile_trans: "i < j ==> j <= k ==> i < (k::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Infty_ub [simp]: "n <= \<infinity>"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma i0_lb [simp]: "(0::inat) <= n"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Infty_ileE [elim!]: "\<infinity> <= Fin m ==> R"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Fin_ile_mono [simp]: "(Fin n <= Fin m) = (n <= m)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma ilessI1: "n <= m ==> n \<noteq> m ==> n < (m::inat)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma ileI1: "m < n ==> iSuc m <= n"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Suc_ile_eq: "Fin (Suc m) <= n = (Fin m < n)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iSuc_ile_mono [simp]: "iSuc n <= iSuc m = (n <= m)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma iless_Suc_eq [simp]: "Fin m < iSuc n = (Fin m <= n)"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma not_iSuc_ilei0 [simp]: "\<not> iSuc n <= 0"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma ile_iSuc [simp]: "n <= iSuc n"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma Fin_ile: "n <= Fin m ==> \<exists>k. n = Fin k"
+by(simp add:inat_defs split:inat_splits, arith?)
+
+lemma chain_incr: "\<forall>i. \<exists>j. Y i < Y j ==> \<exists>j. Fin k < Y j"
+apply (induct_tac "k")
+apply  (simp (no_asm) only: Fin_0)
+apply  (fast intro: ile_iless_trans i0_lb)
+apply (erule exE)
+apply (drule spec)
+apply (erule exE)
+apply (drule ileI1)
+apply (rule iSuc_Fin [THEN subst])
+apply (rule exI)
+apply (erule (1) ile_iless_trans)
+done
+
+ML {*
+val Fin_0 = thm "Fin_0";
+val Suc_ile_eq = thm "Suc_ile_eq";
+val iSuc_Fin = thm "iSuc_Fin";
+val iSuc_Infty = thm "iSuc_Infty";
+val iSuc_mono = thm "iSuc_mono";
+val iSuc_ile_mono = thm "iSuc_ile_mono";
+val not_iSuc_ilei0=thm "not_iSuc_ilei0";
+val iSuc_inject = thm "iSuc_inject";
+val i0_iless_iSuc = thm "i0_iless_iSuc";
+val i0_eq = thm "i0_eq";
+val i0_lb = thm "i0_lb";
+val ile_def = thm "ile_def";
+val ile_refl = thm "ile_refl";
+val Infty_ub = thm "Infty_ub";
+val ilessI1 = thm "ilessI1";
+val ile_iless_trans = thm "ile_iless_trans";
+val ile_trans = thm "ile_trans";
+val ileI1 = thm "ileI1";
+val ile_iSuc = thm "ile_iSuc";
+val Fin_iless_Infty = thm "Fin_iless_Infty";
+val Fin_ile_mono = thm "Fin_ile_mono";
+val chain_incr = thm "chain_incr";
+val Infty_eq = thm "Infty_eq";
+*}
+
+end
+
+
+