--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ZF/Fin.ML Fri May 06 15:02:57 1994 +0200
@@ -0,0 +1,106 @@
+(* Title: ZF/ex/fin.ML
+ ID: $Id$
+ Author: Lawrence C Paulson, Cambridge University Computer Laboratory
+ Copyright 1993 University of Cambridge
+
+Finite powerset operator
+
+could define cardinality?
+
+prove X:Fin(A) ==> EX n:nat. EX f. f:bij(X,n)
+ card(0)=0
+ [| a~:b; b: Fin(A) |] ==> card(cons(a,b)) = succ(card(b))
+
+b: Fin(A) ==> inj(b,b)<=surj(b,b)
+
+Limit(i) ==> Fin(Vfrom(A,i)) <= Un j:i. Fin(Vfrom(A,j))
+Fin(univ(A)) <= univ(A)
+*)
+
+structure Fin = Inductive_Fun
+ (val thy = Arith.thy addconsts [(["Fin"],"i=>i")]
+ val rec_doms = [("Fin","Pow(A)")]
+ val sintrs = ["0 : Fin(A)",
+ "[| a: A; b: Fin(A) |] ==> cons(a,b) : Fin(A)"]
+ val monos = []
+ val con_defs = []
+ val type_intrs = [empty_subsetI, cons_subsetI, PowI]
+ val type_elims = [make_elim PowD]);
+
+store_theory "Fin" Fin.thy;
+
+val [Fin_0I, Fin_consI] = Fin.intrs;
+
+
+goalw Fin.thy Fin.defs "!!A B. A<=B ==> Fin(A) <= Fin(B)";
+by (rtac lfp_mono 1);
+by (REPEAT (rtac Fin.bnd_mono 1));
+by (REPEAT (ares_tac (Pow_mono::basic_monos) 1));
+val Fin_mono = result();
+
+(* A : Fin(B) ==> A <= B *)
+val FinD = Fin.dom_subset RS subsetD RS PowD;
+
+(** Induction on finite sets **)
+
+(*Discharging x~:y entails extra work*)
+val major::prems = goal Fin.thy
+ "[| b: Fin(A); \
+\ P(0); \
+\ !!x y. [| x: A; y: Fin(A); x~:y; P(y) |] ==> P(cons(x,y)) \
+\ |] ==> P(b)";
+by (rtac (major RS Fin.induct) 1);
+by (res_inst_tac [("Q","a:b")] (excluded_middle RS disjE) 2);
+by (etac (cons_absorb RS ssubst) 3 THEN assume_tac 3); (*backtracking!*)
+by (REPEAT (ares_tac prems 1));
+val Fin_induct = result();
+
+(** Simplification for Fin **)
+val Fin_ss = arith_ss addsimps Fin.intrs;
+
+(*The union of two finite sets is finite.*)
+val major::prems = goal Fin.thy
+ "[| b: Fin(A); c: Fin(A) |] ==> b Un c : Fin(A)";
+by (rtac (major RS Fin_induct) 1);
+by (ALLGOALS (asm_simp_tac (Fin_ss addsimps (prems@[Un_0, Un_cons]))));
+val Fin_UnI = result();
+
+(*The union of a set of finite sets is finite.*)
+val [major] = goal Fin.thy "C : Fin(Fin(A)) ==> Union(C) : Fin(A)";
+by (rtac (major RS Fin_induct) 1);
+by (ALLGOALS (asm_simp_tac (Fin_ss addsimps [Union_0, Union_cons, Fin_UnI])));
+val Fin_UnionI = result();
+
+(*Every subset of a finite set is finite.*)
+goal Fin.thy "!!b A. b: Fin(A) ==> ALL z. z<=b --> z: Fin(A)";
+by (etac Fin_induct 1);
+by (simp_tac (Fin_ss addsimps [subset_empty_iff]) 1);
+by (safe_tac (ZF_cs addSDs [subset_cons_iff RS iffD1]));
+by (eres_inst_tac [("b","z")] (cons_Diff RS subst) 2);
+by (ALLGOALS (asm_simp_tac Fin_ss));
+val Fin_subset_lemma = result();
+
+goal Fin.thy "!!c b A. [| c<=b; b: Fin(A) |] ==> c: Fin(A)";
+by (REPEAT (ares_tac [Fin_subset_lemma RS spec RS mp] 1));
+val Fin_subset = result();
+
+val major::prems = goal Fin.thy
+ "[| c: Fin(A); b: Fin(A); \
+\ P(b); \
+\ !!x y. [| x: A; y: Fin(A); x:y; P(y) |] ==> P(y-{x}) \
+\ |] ==> c<=b --> P(b-c)";
+by (rtac (major RS Fin_induct) 1);
+by (rtac (Diff_cons RS ssubst) 2);
+by (ALLGOALS (asm_simp_tac (Fin_ss addsimps (prems@[Diff_0, cons_subset_iff,
+ Diff_subset RS Fin_subset]))));
+val Fin_0_induct_lemma = result();
+
+val prems = goal Fin.thy
+ "[| b: Fin(A); \
+\ P(b); \
+\ !!x y. [| x: A; y: Fin(A); x:y; P(y) |] ==> P(y-{x}) \
+\ |] ==> P(0)";
+by (rtac (Diff_cancel RS subst) 1);
+by (rtac (Fin_0_induct_lemma RS mp) 1);
+by (REPEAT (ares_tac (subset_refl::prems) 1));
+val Fin_0_induct = result();
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ZF/Fin.thy Fri May 06 15:02:57 1994 +0200
@@ -0,0 +1,3 @@
+(*Dummy theory to document dependencies *)
+
+fin = Arith + "inductive" + "constructor" + "intr_elim" + "equalities"
--- a/src/ZF/Makefile Fri May 06 13:50:36 1994 +0200
+++ b/src/ZF/Makefile Fri May 06 15:02:57 1994 +0200
@@ -26,13 +26,13 @@
WF.thy WF.ML Ord.thy Ord.ML Nat.thy Nat.ML \
Epsilon.thy Epsilon.ML Arith.thy Arith.ML Univ.thy Univ.ML \
QUniv.thy QUniv.ML constructor.ML Datatype.ML \
- fin.ML List.ML ListFn.thy ListFn.ML
+ Fin.ML List.ML ListFn.thy ListFn.ML
EX_FILES = ex/ROOT.ML ex/Acc.ML ex/Bin.ML ex/BinFn.ML ex/BinFn.thy\
ex/BT.ML ex/BT_Fn.ML ex/BT_Fn.thy ex/Comb.ML\
- ex/Contract0.ML ex/Contract0.thy ex/counit.ML ex/Data.ML\
+ ex/Contract0.ML ex/Contract0.thy ex/CoUnit.ML ex/Data.ML\
ex/Enum.ML ex/Equiv.ML ex/Equiv.thy ex/Integ.ML ex/Integ.thy\
- ex/ListN.ML ex/llist.ML ex/LList_Eq.ML ex/LListFn.ML ex/LListFn.thy\
+ ex/ListN.ML ex/LList.ML ex/LList_Eq.ML ex/LListFn.ML ex/LListFn.thy\
ex/misc.ML ex/ParContract.ML ex/Primrec0.ML ex/Primrec0.thy\
ex/Prop.ML ex/PropLog.ML ex/PropLog.thy ex/Ramsey.ML ex/Ramsey.thy\
ex/Rmap.ML ex/Term.ML ex/TermFn.ML ex/TermFn.thy ex/TF.ML\