| author | wenzelm | 
| Mon, 09 Oct 2006 02:19:52 +0200 | |
| changeset 20900 | c1ba49ade6a5 | 
| parent 16417 | 9bc16273c2d4 | 
| child 24893 | b8ef7afe3a6b | 
| permissions | -rw-r--r-- | 
| 13163 | 1  | 
(* Title: ZF/func.thy  | 
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ID: $Id$  | 
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Author: Lawrence C Paulson, Cambridge University Computer Laboratory  | 
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Copyright 1991 University of Cambridge  | 
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*)  | 
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header{*Functions, Function Spaces, Lambda-Abstraction*}
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theory func imports equalities Sum begin  | 
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subsection{*The Pi Operator: Dependent Function Space*}
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lemma subset_Sigma_imp_relation: "r <= Sigma(A,B) ==> relation(r)"  | 
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by (simp add: relation_def, blast)  | 
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lemma relation_converse_converse [simp]:  | 
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"relation(r) ==> converse(converse(r)) = r"  | 
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by (simp add: relation_def, blast)  | 
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lemma relation_restrict [simp]: "relation(restrict(r,A))"  | 
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by (simp add: restrict_def relation_def, blast)  | 
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lemma Pi_iff:  | 
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"f: Pi(A,B) <-> function(f) & f<=Sigma(A,B) & A<=domain(f)"  | 
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by (unfold Pi_def, blast)  | 
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(*For upward compatibility with the former definition*)  | 
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lemma Pi_iff_old:  | 
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"f: Pi(A,B) <-> f<=Sigma(A,B) & (ALL x:A. EX! y. <x,y>: f)"  | 
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by (unfold Pi_def function_def, blast)  | 
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lemma fun_is_function: "f: Pi(A,B) ==> function(f)"  | 
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by (simp only: Pi_iff)  | 
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lemma function_imp_Pi:  | 
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"[|function(f); relation(f)|] ==> f \<in> domain(f) -> range(f)"  | 
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by (simp add: Pi_iff relation_def, blast)  | 
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lemma functionI:  | 
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"[| !!x y y'. [| <x,y>:r; <x,y'>:r |] ==> y=y' |] ==> function(r)"  | 
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by (simp add: function_def, blast)  | 
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(*Functions are relations*)  | 
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lemma fun_is_rel: "f: Pi(A,B) ==> f <= Sigma(A,B)"  | 
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by (unfold Pi_def, blast)  | 
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lemma Pi_cong:  | 
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"[| A=A'; !!x. x:A' ==> B(x)=B'(x) |] ==> Pi(A,B) = Pi(A',B')"  | 
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by (simp add: Pi_def cong add: Sigma_cong)  | 
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(*Sigma_cong, Pi_cong NOT given to Addcongs: they cause  | 
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flex-flex pairs and the "Check your prover" error. Most  | 
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Sigmas and Pis are abbreviated as * or -> *)  | 
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(*Weakening one function type to another; see also Pi_type*)  | 
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lemma fun_weaken_type: "[| f: A->B; B<=D |] ==> f: A->D"  | 
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by (unfold Pi_def, best)  | 
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subsection{*Function Application*}
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lemma apply_equality2: "[| <a,b>: f; <a,c>: f; f: Pi(A,B) |] ==> b=c"  | 
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by (unfold Pi_def function_def, blast)  | 
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lemma function_apply_equality: "[| <a,b>: f; function(f) |] ==> f`a = b"  | 
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by (unfold apply_def function_def, blast)  | 
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lemma apply_equality: "[| <a,b>: f; f: Pi(A,B) |] ==> f`a = b"  | 
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apply (unfold Pi_def)  | 
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apply (blast intro: function_apply_equality)  | 
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done  | 
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(*Applying a function outside its domain yields 0*)  | 
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lemma apply_0: "a ~: domain(f) ==> f`a = 0"  | 
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by (unfold apply_def, blast)  | 
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lemma Pi_memberD: "[| f: Pi(A,B); c: f |] ==> EX x:A. c = <x,f`x>"  | 
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apply (frule fun_is_rel)  | 
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apply (blast dest: apply_equality)  | 
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done  | 
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lemma function_apply_Pair: "[| function(f); a : domain(f)|] ==> <a,f`a>: f"  | 
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apply (simp add: function_def, clarify)  | 
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parents: 
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apply (subgoal_tac "f`a = y", blast)  | 
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paulson 
parents: 
13175 
diff
changeset
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apply (simp add: apply_def, blast)  | 
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done  | 
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lemma apply_Pair: "[| f: Pi(A,B); a:A |] ==> <a,f`a>: f"  | 
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apply (simp add: Pi_iff)  | 
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apply (blast intro: function_apply_Pair)  | 
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done  | 
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(*Conclusion is flexible -- use res_inst_tac or else apply_funtype below!*)  | 
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lemma apply_type [TC]: "[| f: Pi(A,B); a:A |] ==> f`a : B(a)"  | 
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by (blast intro: apply_Pair dest: fun_is_rel)  | 
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(*This version is acceptable to the simplifier*)  | 
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lemma apply_funtype: "[| f: A->B; a:A |] ==> f`a : B"  | 
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by (blast dest: apply_type)  | 
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lemma apply_iff: "f: Pi(A,B) ==> <a,b>: f <-> a:A & f`a = b"  | 
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apply (frule fun_is_rel)  | 
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apply (blast intro!: apply_Pair apply_equality)  | 
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done  | 
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(*Refining one Pi type to another*)  | 
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lemma Pi_type: "[| f: Pi(A,C); !!x. x:A ==> f`x : B(x) |] ==> f : Pi(A,B)"  | 
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apply (simp only: Pi_iff)  | 
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apply (blast dest: function_apply_equality)  | 
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done  | 
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(*Such functions arise in non-standard datatypes, ZF/ex/Ntree for instance*)  | 
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lemma Pi_Collect_iff:  | 
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     "(f : Pi(A, %x. {y:B(x). P(x,y)}))
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<-> f : Pi(A,B) & (ALL x: A. P(x, f`x))"  | 
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by (blast intro: Pi_type dest: apply_type)  | 
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lemma Pi_weaken_type:  | 
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"[| f : Pi(A,B); !!x. x:A ==> B(x)<=C(x) |] ==> f : Pi(A,C)"  | 
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by (blast intro: Pi_type dest: apply_type)  | 
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(** Elimination of membership in a function **)  | 
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lemma domain_type: "[| <a,b> : f; f: Pi(A,B) |] ==> a : A"  | 
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by (blast dest: fun_is_rel)  | 
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lemma range_type: "[| <a,b> : f; f: Pi(A,B) |] ==> b : B(a)"  | 
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by (blast dest: fun_is_rel)  | 
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lemma Pair_mem_PiD: "[| <a,b>: f; f: Pi(A,B) |] ==> a:A & b:B(a) & f`a = b"  | 
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by (blast intro: domain_type range_type apply_equality)  | 
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subsection{*Lambda Abstraction*}
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lemma lamI: "a:A ==> <a,b(a)> : (lam x:A. b(x))"  | 
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apply (unfold lam_def)  | 
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apply (erule RepFunI)  | 
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done  | 
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lemma lamE:  | 
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"[| p: (lam x:A. b(x)); !!x.[| x:A; p=<x,b(x)> |] ==> P  | 
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|] ==> P"  | 
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by (simp add: lam_def, blast)  | 
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lemma lamD: "[| <a,c>: (lam x:A. b(x)) |] ==> c = b(a)"  | 
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by (simp add: lam_def)  | 
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lemma lam_type [TC]:  | 
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"[| !!x. x:A ==> b(x): B(x) |] ==> (lam x:A. b(x)) : Pi(A,B)"  | 
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by (simp add: lam_def Pi_def function_def, blast)  | 
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lemma lam_funtype: "(lam x:A. b(x)) : A -> {b(x). x:A}"
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parents: 
13175 
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changeset
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by (blast intro: lam_type)  | 
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lemma function_lam: "function (lam x:A. b(x))"  | 
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by (simp add: function_def lam_def)  | 
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lemma relation_lam: "relation (lam x:A. b(x))"  | 
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by (simp add: relation_def lam_def)  | 
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lemma beta_if [simp]: "(lam x:A. b(x)) ` a = (if a : A then b(a) else 0)"  | 
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paulson 
parents: 
13175 
diff
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by (simp add: apply_def lam_def, blast)  | 
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paulson 
parents: 
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parents: 
13174 
diff
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lemma beta: "a : A ==> (lam x:A. b(x)) ` a = b(a)"  | 
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312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
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by (simp add: apply_def lam_def, blast)  | 
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lemma lam_empty [simp]: "(lam x:0. b(x)) = 0"  | 
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by (simp add: lam_def)  | 
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lemma domain_lam [simp]: "domain(Lambda(A,b)) = A"  | 
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by (simp add: lam_def, blast)  | 
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(*congruence rule for lambda abstraction*)  | 
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lemma lam_cong [cong]:  | 
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"[| A=A'; !!x. x:A' ==> b(x)=b'(x) |] ==> Lambda(A,b) = Lambda(A',b')"  | 
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by (simp only: lam_def cong add: RepFun_cong)  | 
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lemma lam_theI:  | 
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"(!!x. x:A ==> EX! y. Q(x,y)) ==> EX f. ALL x:A. Q(x, f`x)"  | 
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apply (rule_tac x = "lam x: A. THE y. Q (x,y)" in exI)  | 
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paulson 
parents: 
13175 
diff
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apply simp  | 
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apply (blast intro: theI)  | 
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done  | 
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lemma lam_eqE: "[| (lam x:A. f(x)) = (lam x:A. g(x)); a:A |] ==> f(a)=g(a)"  | 
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by (fast intro!: lamI elim: equalityE lamE)  | 
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(*Empty function spaces*)  | 
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lemma Pi_empty1 [simp]: "Pi(0,A) = {0}"
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by (unfold Pi_def function_def, blast)  | 
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(*The singleton function*)  | 
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lemma singleton_fun [simp]: "{<a,b>} : {a} -> {b}"
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by (unfold Pi_def function_def, blast)  | 
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lemma Pi_empty2 [simp]: "(A->0) = (if A=0 then {0} else 0)"
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by (unfold Pi_def function_def, force)  | 
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lemma fun_space_empty_iff [iff]: "(A->X)=0 \<longleftrightarrow> X=0 & (A \<noteq> 0)"  | 
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apply auto  | 
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apply (fast intro!: equals0I intro: lam_type)  | 
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done  | 
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subsection{*Extensionality*}
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(*Semi-extensionality!*)  | 
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lemma fun_subset:  | 
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"[| f : Pi(A,B); g: Pi(C,D); A<=C;  | 
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!!x. x:A ==> f`x = g`x |] ==> f<=g"  | 
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by (force dest: Pi_memberD intro: apply_Pair)  | 
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lemma fun_extension:  | 
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"[| f : Pi(A,B); g: Pi(A,D);  | 
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!!x. x:A ==> f`x = g`x |] ==> f=g"  | 
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by (blast del: subsetI intro: subset_refl sym fun_subset)  | 
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lemma eta [simp]: "f : Pi(A,B) ==> (lam x:A. f`x) = f"  | 
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apply (rule fun_extension)  | 
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apply (auto simp add: lam_type apply_type beta)  | 
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done  | 
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lemma fun_extension_iff:  | 
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"[| f:Pi(A,B); g:Pi(A,C) |] ==> (ALL a:A. f`a = g`a) <-> f=g"  | 
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by (blast intro: fun_extension)  | 
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(*thm by Mark Staples, proof by lcp*)  | 
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lemma fun_subset_eq: "[| f:Pi(A,B); g:Pi(A,C) |] ==> f <= g <-> (f = g)"  | 
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by (blast dest: apply_Pair  | 
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intro: fun_extension apply_equality [symmetric])  | 
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(*Every element of Pi(A,B) may be expressed as a lambda abstraction!*)  | 
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lemma Pi_lamE:  | 
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assumes major: "f: Pi(A,B)"  | 
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and minor: "!!b. [| ALL x:A. b(x):B(x); f = (lam x:A. b(x)) |] ==> P"  | 
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shows "P"  | 
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apply (rule minor)  | 
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apply (rule_tac [2] eta [symmetric])  | 
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apply (blast intro: major apply_type)+  | 
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done  | 
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subsection{*Images of Functions*}
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| 13163 | 248  | 
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lemma image_lam: "C <= A ==> (lam x:A. b(x)) `` C = {b(x). x:C}"
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by (unfold lam_def, blast)  | 
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lemma Repfun_function_if:  | 
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"function(f)  | 
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      ==> {f`x. x:C} = (if C <= domain(f) then f``C else cons(0,f``C))";
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apply simp  | 
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apply (intro conjI impI)  | 
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apply (blast dest: function_apply_equality intro: function_apply_Pair)  | 
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apply (rule equalityI)  | 
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apply (blast intro!: function_apply_Pair apply_0)  | 
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apply (blast dest: function_apply_equality intro: apply_0 [symmetric])  | 
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done  | 
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(*For this lemma and the next, the right-hand side could equivalently  | 
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264  | 
  be written \<Union>x\<in>C. {f`x} *)
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lemma image_function:  | 
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     "[| function(f);  C <= domain(f) |] ==> f``C = {f`x. x:C}";
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by (simp add: Repfun_function_if)  | 
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lemma image_fun: "[| f : Pi(A,B);  C <= A |] ==> f``C = {f`x. x:C}"
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| 13174 | 270  | 
apply (simp add: Pi_iff)  | 
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apply (blast intro: image_function)  | 
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done  | 
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lemma image_eq_UN:  | 
275  | 
  assumes f: "f \<in> Pi(A,B)" "C \<subseteq> A" shows "f``C = (\<Union>x\<in>C. {f ` x})"
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by (auto simp add: image_fun [OF f])  | 
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lemma Pi_image_cons:  | 
279  | 
"[| f: Pi(A,B); x: A |] ==> f `` cons(x,y) = cons(f`x, f``y)"  | 
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by (blast dest: apply_equality apply_Pair)  | 
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| 124 | 282  | 
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subsection{*Properties of @{term "restrict(f,A)"}*}
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| 13163 | 284  | 
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lemma restrict_subset: "restrict(f,A) <= f"  | 
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by (unfold restrict_def, blast)  | 
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lemma function_restrictI:  | 
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"function(f) ==> function(restrict(f,A))"  | 
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by (unfold restrict_def function_def, blast)  | 
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lemma restrict_type2: "[| f: Pi(C,B); A<=C |] ==> restrict(f,A) : Pi(A,B)"  | 
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by (simp add: Pi_iff function_def restrict_def, blast)  | 
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| 13179 | 295  | 
lemma restrict: "restrict(f,A) ` a = (if a : A then f`a else 0)"  | 
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paulson 
parents: 
13175 
diff
changeset
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296  | 
by (simp add: apply_def restrict_def, blast)  | 
| 13163 | 297  | 
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298  | 
lemma restrict_empty [simp]: "restrict(f,0) = 0"  | 
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| 13179 | 299  | 
by (unfold restrict_def, simp)  | 
| 13163 | 300  | 
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lemma restrict_iff: "z \<in> restrict(r,A) \<longleftrightarrow> z \<in> r & (\<exists>x\<in>A. \<exists>y. z = \<langle>x, y\<rangle>)"  | 
302  | 
by (simp add: restrict_def)  | 
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| 13163 | 304  | 
lemma restrict_restrict [simp]:  | 
305  | 
"restrict(restrict(r,A),B) = restrict(r, A Int B)"  | 
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by (unfold restrict_def, blast)  | 
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lemma domain_restrict [simp]: "domain(restrict(f,C)) = domain(f) Int C"  | 
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apply (unfold restrict_def)  | 
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apply (auto simp add: domain_def)  | 
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done  | 
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lemma restrict_idem: "f <= Sigma(A,B) ==> restrict(f,A) = f"  | 
| 13163 | 314  | 
by (simp add: restrict_def, blast)  | 
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| 13248 | 316  | 
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(*converse probably holds too*)  | 
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lemma domain_restrict_idem:  | 
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"[| domain(r) <= A; relation(r) |] ==> restrict(r,A) = r"  | 
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by (simp add: restrict_def relation_def, blast)  | 
|
321  | 
||
322  | 
lemma domain_restrict_lam [simp]: "domain(restrict(Lambda(A,f),C)) = A Int C"  | 
|
323  | 
apply (unfold restrict_def lam_def)  | 
|
324  | 
apply (rule equalityI)  | 
|
325  | 
apply (auto simp add: domain_iff)  | 
|
326  | 
done  | 
|
327  | 
||
| 13163 | 328  | 
lemma restrict_if [simp]: "restrict(f,A) ` a = (if a : A then f`a else 0)"  | 
329  | 
by (simp add: restrict apply_0)  | 
|
330  | 
||
331  | 
lemma restrict_lam_eq:  | 
|
332  | 
"A<=C ==> restrict(lam x:C. b(x), A) = (lam x:A. b(x))"  | 
|
333  | 
by (unfold restrict_def lam_def, auto)  | 
|
334  | 
||
335  | 
lemma fun_cons_restrict_eq:  | 
|
336  | 
"f : cons(a, b) -> B ==> f = cons(<a, f ` a>, restrict(f, b))"  | 
|
337  | 
apply (rule equalityI)  | 
|
| 13248 | 338  | 
prefer 2 apply (blast intro: apply_Pair restrict_subset [THEN subsetD])  | 
| 13163 | 339  | 
apply (auto dest!: Pi_memberD simp add: restrict_def lam_def)  | 
340  | 
done  | 
|
341  | 
||
342  | 
||
| 13355 | 343  | 
subsection{*Unions of Functions*}
 | 
| 13163 | 344  | 
|
345  | 
(** The Union of a set of COMPATIBLE functions is a function **)  | 
|
346  | 
||
347  | 
lemma function_Union:  | 
|
348  | 
"[| ALL x:S. function(x);  | 
|
349  | 
ALL x:S. ALL y:S. x<=y | y<=x |]  | 
|
350  | 
==> function(Union(S))"  | 
|
351  | 
by (unfold function_def, blast)  | 
|
352  | 
||
353  | 
lemma fun_Union:  | 
|
354  | 
"[| ALL f:S. EX C D. f:C->D;  | 
|
355  | 
ALL f:S. ALL y:S. f<=y | y<=f |] ==>  | 
|
356  | 
Union(S) : domain(Union(S)) -> range(Union(S))"  | 
|
357  | 
apply (unfold Pi_def)  | 
|
358  | 
apply (blast intro!: rel_Union function_Union)  | 
|
359  | 
done  | 
|
360  | 
||
| 13174 | 361  | 
lemma gen_relation_Union [rule_format]:  | 
362  | 
"\<forall>f\<in>F. relation(f) \<Longrightarrow> relation(Union(F))"  | 
|
363  | 
by (simp add: relation_def)  | 
|
364  | 
||
| 13163 | 365  | 
|
366  | 
(** The Union of 2 disjoint functions is a function **)  | 
|
367  | 
||
368  | 
lemmas Un_rls = Un_subset_iff SUM_Un_distrib1 prod_Un_distrib2  | 
|
369  | 
subset_trans [OF _ Un_upper1]  | 
|
370  | 
subset_trans [OF _ Un_upper2]  | 
|
371  | 
||
372  | 
lemma fun_disjoint_Un:  | 
|
373  | 
"[| f: A->B; g: C->D; A Int C = 0 |]  | 
|
374  | 
==> (f Un g) : (A Un C) -> (B Un D)"  | 
|
375  | 
(*Prove the product and domain subgoals using distributive laws*)  | 
|
376  | 
apply (simp add: Pi_iff extension Un_rls)  | 
|
377  | 
apply (unfold function_def, blast)  | 
|
378  | 
done  | 
|
379  | 
||
| 13179 | 380  | 
lemma fun_disjoint_apply1: "a \<notin> domain(g) ==> (f Un g)`a = f`a"  | 
381  | 
by (simp add: apply_def, blast)  | 
|
| 13163 | 382  | 
|
| 13179 | 383  | 
lemma fun_disjoint_apply2: "c \<notin> domain(f) ==> (f Un g)`c = g`c"  | 
384  | 
by (simp add: apply_def, blast)  | 
|
| 13163 | 385  | 
|
| 13355 | 386  | 
subsection{*Domain and Range of a Function or Relation*}
 | 
| 13163 | 387  | 
|
388  | 
lemma domain_of_fun: "f : Pi(A,B) ==> domain(f)=A"  | 
|
389  | 
by (unfold Pi_def, blast)  | 
|
390  | 
||
391  | 
lemma apply_rangeI: "[| f : Pi(A,B); a: A |] ==> f`a : range(f)"  | 
|
392  | 
by (erule apply_Pair [THEN rangeI], assumption)  | 
|
393  | 
||
394  | 
lemma range_of_fun: "f : Pi(A,B) ==> f : A->range(f)"  | 
|
395  | 
by (blast intro: Pi_type apply_rangeI)  | 
|
396  | 
||
| 13355 | 397  | 
subsection{*Extensions of Functions*}
 | 
| 13163 | 398  | 
|
399  | 
lemma fun_extend:  | 
|
400  | 
"[| f: A->B; c~:A |] ==> cons(<c,b>,f) : cons(c,A) -> cons(b,B)"  | 
|
401  | 
apply (frule singleton_fun [THEN fun_disjoint_Un], blast)  | 
|
402  | 
apply (simp add: cons_eq)  | 
|
403  | 
done  | 
|
404  | 
||
405  | 
lemma fun_extend3:  | 
|
406  | 
"[| f: A->B; c~:A; b: B |] ==> cons(<c,b>,f) : cons(c,A) -> B"  | 
|
407  | 
by (blast intro: fun_extend [THEN fun_weaken_type])  | 
|
408  | 
||
| 
13176
 
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paulson 
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13175 
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changeset
 | 
409  | 
lemma extend_apply:  | 
| 
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
410  | 
"c ~: domain(f) ==> cons(<c,b>,f)`a = (if a=c then b else f`a)"  | 
| 
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
411  | 
by (auto simp add: apply_def)  | 
| 13163 | 412  | 
|
| 
13176
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
413  | 
lemma fun_extend_apply [simp]:  | 
| 
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
414  | 
"[| f: A->B; c~:A |] ==> cons(<c,b>,f)`a = (if a=c then b else f`a)"  | 
| 
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
415  | 
apply (rule extend_apply)  | 
| 
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
416  | 
apply (simp add: Pi_def, blast)  | 
| 13163 | 417  | 
done  | 
418  | 
||
419  | 
lemmas singleton_apply = apply_equality [OF singletonI singleton_fun, simp]  | 
|
420  | 
||
421  | 
(*For Finite.ML. Inclusion of right into left is easy*)  | 
|
422  | 
lemma cons_fun_eq:  | 
|
| 13269 | 423  | 
     "c ~: A ==> cons(c,A) -> B = (\<Union>f \<in> A->B. \<Union>b\<in>B. {cons(<c,b>, f)})"
 | 
| 13163 | 424  | 
apply (rule equalityI)  | 
425  | 
apply (safe elim!: fun_extend3)  | 
|
426  | 
(*Inclusion of left into right*)  | 
|
427  | 
apply (subgoal_tac "restrict (x, A) : A -> B")  | 
|
428  | 
prefer 2 apply (blast intro: restrict_type2)  | 
|
429  | 
apply (rule UN_I, assumption)  | 
|
430  | 
apply (rule apply_funtype [THEN UN_I])  | 
|
431  | 
apply assumption  | 
|
432  | 
apply (rule consI1)  | 
|
433  | 
apply (simp (no_asm))  | 
|
434  | 
apply (rule fun_extension)  | 
|
435  | 
apply assumption  | 
|
436  | 
apply (blast intro: fun_extend)  | 
|
| 
13176
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
437  | 
apply (erule consE, simp_all)  | 
| 13163 | 438  | 
done  | 
439  | 
||
| 13269 | 440  | 
lemma succ_fun_eq: "succ(n) -> B = (\<Union>f \<in> n->B. \<Union>b\<in>B. {cons(<n,b>, f)})"
 | 
441  | 
by (simp add: succ_def mem_not_refl cons_fun_eq)  | 
|
442  | 
||
| 13355 | 443  | 
|
444  | 
subsection{*Function Updates*}
 | 
|
445  | 
||
446  | 
constdefs  | 
|
447  | 
update :: "[i,i,i] => i"  | 
|
448  | 
"update(f,a,b) == lam x: cons(a, domain(f)). if(x=a, b, f`x)"  | 
|
449  | 
||
450  | 
nonterminals  | 
|
451  | 
updbinds updbind  | 
|
452  | 
||
453  | 
syntax  | 
|
454  | 
||
455  | 
(* Let expressions *)  | 
|
456  | 
||
457  | 
  "_updbind"    :: "[i, i] => updbind"               ("(2_ :=/ _)")
 | 
|
458  | 
  ""            :: "updbind => updbinds"             ("_")
 | 
|
459  | 
  "_updbinds"   :: "[updbind, updbinds] => updbinds" ("_,/ _")
 | 
|
460  | 
  "_Update"     :: "[i, updbinds] => i"              ("_/'((_)')" [900,0] 900)
 | 
|
461  | 
||
462  | 
translations  | 
|
463  | 
"_Update (f, _updbinds(b,bs))" == "_Update (_Update(f,b), bs)"  | 
|
464  | 
"f(x:=y)" == "update(f,x,y)"  | 
|
465  | 
||
466  | 
||
467  | 
lemma update_apply [simp]: "f(x:=y) ` z = (if z=x then y else f`z)"  | 
|
468  | 
apply (simp add: update_def)  | 
|
| 14153 | 469  | 
apply (case_tac "z \<in> domain(f)")  | 
| 13355 | 470  | 
apply (simp_all add: apply_0)  | 
471  | 
done  | 
|
472  | 
||
473  | 
lemma update_idem: "[| f`x = y; f: Pi(A,B); x: A |] ==> f(x:=y) = f"  | 
|
474  | 
apply (unfold update_def)  | 
|
475  | 
apply (simp add: domain_of_fun cons_absorb)  | 
|
476  | 
apply (rule fun_extension)  | 
|
477  | 
apply (best intro: apply_type if_type lam_type, assumption, simp)  | 
|
478  | 
done  | 
|
479  | 
||
480  | 
||
481  | 
(* [| f: Pi(A, B); x:A |] ==> f(x := f`x) = f *)  | 
|
482  | 
declare refl [THEN update_idem, simp]  | 
|
483  | 
||
484  | 
lemma domain_update [simp]: "domain(f(x:=y)) = cons(x, domain(f))"  | 
|
485  | 
by (unfold update_def, simp)  | 
|
486  | 
||
| 14046 | 487  | 
lemma update_type: "[| f:Pi(A,B); x : A; y: B(x) |] ==> f(x:=y) : Pi(A, B)"  | 
| 13355 | 488  | 
apply (unfold update_def)  | 
489  | 
apply (simp add: domain_of_fun cons_absorb apply_funtype lam_type)  | 
|
490  | 
done  | 
|
491  | 
||
492  | 
||
| 13357 | 493  | 
subsection{*Monotonicity Theorems*}
 | 
494  | 
||
495  | 
subsubsection{*Replacement in its Various Forms*}
 | 
|
496  | 
||
497  | 
(*Not easy to express monotonicity in P, since any "bigger" predicate  | 
|
498  | 
would have to be single-valued*)  | 
|
499  | 
lemma Replace_mono: "A<=B ==> Replace(A,P) <= Replace(B,P)"  | 
|
500  | 
by (blast elim!: ReplaceE)  | 
|
501  | 
||
502  | 
lemma RepFun_mono: "A<=B ==> {f(x). x:A} <= {f(x). x:B}"
 | 
|
503  | 
by blast  | 
|
504  | 
||
505  | 
lemma Pow_mono: "A<=B ==> Pow(A) <= Pow(B)"  | 
|
506  | 
by blast  | 
|
507  | 
||
508  | 
lemma Union_mono: "A<=B ==> Union(A) <= Union(B)"  | 
|
509  | 
by blast  | 
|
510  | 
||
511  | 
lemma UN_mono:  | 
|
| 
13615
 
449a70d88b38
Numerous cosmetic changes, prompted by the new simplifier
 
paulson 
parents: 
13357 
diff
changeset
 | 
512  | 
"[| A<=C; !!x. x:A ==> B(x)<=D(x) |] ==> (\<Union>x\<in>A. B(x)) <= (\<Union>x\<in>C. D(x))"  | 
| 13357 | 513  | 
by blast  | 
514  | 
||
515  | 
(*Intersection is ANTI-monotonic. There are TWO premises! *)  | 
|
| 
14095
 
a1ba833d6b61
Changed many Intersection rules from i:I to I~=0 to avoid introducing a new
 
paulson 
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14046 
diff
changeset
 | 
516  | 
lemma Inter_anti_mono: "[| A<=B; A\<noteq>0 |] ==> Inter(B) <= Inter(A)"  | 
| 13357 | 517  | 
by blast  | 
518  | 
||
519  | 
lemma cons_mono: "C<=D ==> cons(a,C) <= cons(a,D)"  | 
|
520  | 
by blast  | 
|
521  | 
||
522  | 
lemma Un_mono: "[| A<=C; B<=D |] ==> A Un B <= C Un D"  | 
|
523  | 
by blast  | 
|
524  | 
||
525  | 
lemma Int_mono: "[| A<=C; B<=D |] ==> A Int B <= C Int D"  | 
|
526  | 
by blast  | 
|
527  | 
||
528  | 
lemma Diff_mono: "[| A<=C; D<=B |] ==> A-B <= C-D"  | 
|
529  | 
by blast  | 
|
530  | 
||
531  | 
subsubsection{*Standard Products, Sums and Function Spaces *}
 | 
|
532  | 
||
533  | 
lemma Sigma_mono [rule_format]:  | 
|
534  | 
"[| A<=C; !!x. x:A --> B(x) <= D(x) |] ==> Sigma(A,B) <= Sigma(C,D)"  | 
|
535  | 
by blast  | 
|
536  | 
||
537  | 
lemma sum_mono: "[| A<=C; B<=D |] ==> A+B <= C+D"  | 
|
538  | 
by (unfold sum_def, blast)  | 
|
539  | 
||
540  | 
(*Note that B->A and C->A are typically disjoint!*)  | 
|
541  | 
lemma Pi_mono: "B<=C ==> A->B <= A->C"  | 
|
542  | 
by (blast intro: lam_type elim: Pi_lamE)  | 
|
543  | 
||
544  | 
lemma lam_mono: "A<=B ==> Lambda(A,c) <= Lambda(B,c)"  | 
|
545  | 
apply (unfold lam_def)  | 
|
546  | 
apply (erule RepFun_mono)  | 
|
547  | 
done  | 
|
548  | 
||
549  | 
subsubsection{*Converse, Domain, Range, Field*}
 | 
|
550  | 
||
551  | 
lemma converse_mono: "r<=s ==> converse(r) <= converse(s)"  | 
|
552  | 
by blast  | 
|
553  | 
||
554  | 
lemma domain_mono: "r<=s ==> domain(r)<=domain(s)"  | 
|
555  | 
by blast  | 
|
556  | 
||
557  | 
lemmas domain_rel_subset = subset_trans [OF domain_mono domain_subset]  | 
|
558  | 
||
559  | 
lemma range_mono: "r<=s ==> range(r)<=range(s)"  | 
|
560  | 
by blast  | 
|
561  | 
||
562  | 
lemmas range_rel_subset = subset_trans [OF range_mono range_subset]  | 
|
563  | 
||
564  | 
lemma field_mono: "r<=s ==> field(r)<=field(s)"  | 
|
565  | 
by blast  | 
|
566  | 
||
567  | 
lemma field_rel_subset: "r <= A*A ==> field(r) <= A"  | 
|
568  | 
by (erule field_mono [THEN subset_trans], blast)  | 
|
569  | 
||
570  | 
||
571  | 
subsubsection{*Images*}
 | 
|
572  | 
||
573  | 
lemma image_pair_mono:  | 
|
574  | 
"[| !! x y. <x,y>:r ==> <x,y>:s; A<=B |] ==> r``A <= s``B"  | 
|
575  | 
by blast  | 
|
576  | 
||
577  | 
lemma vimage_pair_mono:  | 
|
578  | 
"[| !! x y. <x,y>:r ==> <x,y>:s; A<=B |] ==> r-``A <= s-``B"  | 
|
579  | 
by blast  | 
|
580  | 
||
581  | 
lemma image_mono: "[| r<=s; A<=B |] ==> r``A <= s``B"  | 
|
582  | 
by blast  | 
|
583  | 
||
584  | 
lemma vimage_mono: "[| r<=s; A<=B |] ==> r-``A <= s-``B"  | 
|
585  | 
by blast  | 
|
586  | 
||
587  | 
lemma Collect_mono:  | 
|
588  | 
"[| A<=B; !!x. x:A ==> P(x) --> Q(x) |] ==> Collect(A,P) <= Collect(B,Q)"  | 
|
589  | 
by blast  | 
|
590  | 
||
591  | 
(*Used in intr_elim.ML and in individual datatype definitions*)  | 
|
592  | 
lemmas basic_monos = subset_refl imp_refl disj_mono conj_mono ex_mono  | 
|
593  | 
Collect_mono Part_mono in_mono  | 
|
594  | 
||
| 13163 | 595  | 
ML  | 
596  | 
{*
 | 
|
597  | 
val Pi_iff = thm "Pi_iff";  | 
|
598  | 
val Pi_iff_old = thm "Pi_iff_old";  | 
|
599  | 
val fun_is_function = thm "fun_is_function";  | 
|
600  | 
val fun_is_rel = thm "fun_is_rel";  | 
|
601  | 
val Pi_cong = thm "Pi_cong";  | 
|
602  | 
val fun_weaken_type = thm "fun_weaken_type";  | 
|
603  | 
val apply_equality2 = thm "apply_equality2";  | 
|
604  | 
val function_apply_equality = thm "function_apply_equality";  | 
|
605  | 
val apply_equality = thm "apply_equality";  | 
|
606  | 
val apply_0 = thm "apply_0";  | 
|
607  | 
val Pi_memberD = thm "Pi_memberD";  | 
|
608  | 
val function_apply_Pair = thm "function_apply_Pair";  | 
|
609  | 
val apply_Pair = thm "apply_Pair";  | 
|
610  | 
val apply_type = thm "apply_type";  | 
|
611  | 
val apply_funtype = thm "apply_funtype";  | 
|
612  | 
val apply_iff = thm "apply_iff";  | 
|
613  | 
val Pi_type = thm "Pi_type";  | 
|
614  | 
val Pi_Collect_iff = thm "Pi_Collect_iff";  | 
|
615  | 
val Pi_weaken_type = thm "Pi_weaken_type";  | 
|
616  | 
val domain_type = thm "domain_type";  | 
|
617  | 
val range_type = thm "range_type";  | 
|
618  | 
val Pair_mem_PiD = thm "Pair_mem_PiD";  | 
|
619  | 
val lamI = thm "lamI";  | 
|
620  | 
val lamE = thm "lamE";  | 
|
621  | 
val lamD = thm "lamD";  | 
|
622  | 
val lam_type = thm "lam_type";  | 
|
623  | 
val lam_funtype = thm "lam_funtype";  | 
|
624  | 
val beta = thm "beta";  | 
|
625  | 
val lam_empty = thm "lam_empty";  | 
|
626  | 
val domain_lam = thm "domain_lam";  | 
|
627  | 
val lam_cong = thm "lam_cong";  | 
|
628  | 
val lam_theI = thm "lam_theI";  | 
|
629  | 
val lam_eqE = thm "lam_eqE";  | 
|
630  | 
val Pi_empty1 = thm "Pi_empty1";  | 
|
631  | 
val singleton_fun = thm "singleton_fun";  | 
|
632  | 
val Pi_empty2 = thm "Pi_empty2";  | 
|
633  | 
val fun_space_empty_iff = thm "fun_space_empty_iff";  | 
|
634  | 
val fun_subset = thm "fun_subset";  | 
|
635  | 
val fun_extension = thm "fun_extension";  | 
|
636  | 
val eta = thm "eta";  | 
|
637  | 
val fun_extension_iff = thm "fun_extension_iff";  | 
|
638  | 
val fun_subset_eq = thm "fun_subset_eq";  | 
|
639  | 
val Pi_lamE = thm "Pi_lamE";  | 
|
640  | 
val image_lam = thm "image_lam";  | 
|
641  | 
val image_fun = thm "image_fun";  | 
|
642  | 
val Pi_image_cons = thm "Pi_image_cons";  | 
|
643  | 
val restrict_subset = thm "restrict_subset";  | 
|
644  | 
val function_restrictI = thm "function_restrictI";  | 
|
645  | 
val restrict_type2 = thm "restrict_type2";  | 
|
646  | 
val restrict = thm "restrict";  | 
|
647  | 
val restrict_empty = thm "restrict_empty";  | 
|
648  | 
val domain_restrict_lam = thm "domain_restrict_lam";  | 
|
649  | 
val restrict_restrict = thm "restrict_restrict";  | 
|
650  | 
val domain_restrict = thm "domain_restrict";  | 
|
651  | 
val restrict_idem = thm "restrict_idem";  | 
|
652  | 
val restrict_if = thm "restrict_if";  | 
|
653  | 
val restrict_lam_eq = thm "restrict_lam_eq";  | 
|
654  | 
val fun_cons_restrict_eq = thm "fun_cons_restrict_eq";  | 
|
655  | 
val function_Union = thm "function_Union";  | 
|
656  | 
val fun_Union = thm "fun_Union";  | 
|
657  | 
val fun_disjoint_Un = thm "fun_disjoint_Un";  | 
|
658  | 
val fun_disjoint_apply1 = thm "fun_disjoint_apply1";  | 
|
659  | 
val fun_disjoint_apply2 = thm "fun_disjoint_apply2";  | 
|
660  | 
val domain_of_fun = thm "domain_of_fun";  | 
|
661  | 
val apply_rangeI = thm "apply_rangeI";  | 
|
662  | 
val range_of_fun = thm "range_of_fun";  | 
|
663  | 
val fun_extend = thm "fun_extend";  | 
|
664  | 
val fun_extend3 = thm "fun_extend3";  | 
|
| 
13176
 
312bd350579b
conversion of Perm to Isar.  Strengthening of comp_fun_apply
 
paulson 
parents: 
13175 
diff
changeset
 | 
665  | 
val fun_extend_apply = thm "fun_extend_apply";  | 
| 13163 | 666  | 
val singleton_apply = thm "singleton_apply";  | 
667  | 
val cons_fun_eq = thm "cons_fun_eq";  | 
|
| 13355 | 668  | 
|
669  | 
val update_def = thm "update_def";  | 
|
670  | 
val update_apply = thm "update_apply";  | 
|
671  | 
val update_idem = thm "update_idem";  | 
|
672  | 
val domain_update = thm "domain_update";  | 
|
673  | 
val update_type = thm "update_type";  | 
|
| 13357 | 674  | 
|
675  | 
val Replace_mono = thm "Replace_mono";  | 
|
676  | 
val RepFun_mono = thm "RepFun_mono";  | 
|
677  | 
val Pow_mono = thm "Pow_mono";  | 
|
678  | 
val Union_mono = thm "Union_mono";  | 
|
679  | 
val UN_mono = thm "UN_mono";  | 
|
680  | 
val Inter_anti_mono = thm "Inter_anti_mono";  | 
|
681  | 
val cons_mono = thm "cons_mono";  | 
|
682  | 
val Un_mono = thm "Un_mono";  | 
|
683  | 
val Int_mono = thm "Int_mono";  | 
|
684  | 
val Diff_mono = thm "Diff_mono";  | 
|
685  | 
val Sigma_mono = thm "Sigma_mono";  | 
|
686  | 
val sum_mono = thm "sum_mono";  | 
|
687  | 
val Pi_mono = thm "Pi_mono";  | 
|
688  | 
val lam_mono = thm "lam_mono";  | 
|
689  | 
val converse_mono = thm "converse_mono";  | 
|
690  | 
val domain_mono = thm "domain_mono";  | 
|
691  | 
val domain_rel_subset = thm "domain_rel_subset";  | 
|
692  | 
val range_mono = thm "range_mono";  | 
|
693  | 
val range_rel_subset = thm "range_rel_subset";  | 
|
694  | 
val field_mono = thm "field_mono";  | 
|
695  | 
val field_rel_subset = thm "field_rel_subset";  | 
|
696  | 
val image_pair_mono = thm "image_pair_mono";  | 
|
697  | 
val vimage_pair_mono = thm "vimage_pair_mono";  | 
|
698  | 
val image_mono = thm "image_mono";  | 
|
699  | 
val vimage_mono = thm "vimage_mono";  | 
|
700  | 
val Collect_mono = thm "Collect_mono";  | 
|
701  | 
||
702  | 
val basic_monos = thms "basic_monos";  | 
|
| 13163 | 703  | 
*}  | 
704  | 
||
705  | 
end  |