--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ZF/Univ.thy Thu Sep 16 12:20:38 1993 +0200
@@ -0,0 +1,34 @@
+(* Title: ZF/univ.thy
+ ID: $Id$
+ Author: Lawrence C Paulson, Cambridge University Computer Laboratory
+ Copyright 1992 University of Cambridge
+
+The cumulative hierarchy and a small universe for recursive types
+
+Standard notation for Vset(i) is V(i), but users might want V for a variable
+*)
+
+Univ = Arith + Sum +
+consts
+ Limit :: "i=>o"
+ Vfrom :: "[i,i]=>i"
+ Vset :: "i=>i"
+ Vrec :: "[i, [i,i]=>i] =>i"
+ univ :: "i=>i"
+
+translations
+ (*Apparently a bug prevents using "Vset" == "Vfrom(0)" *)
+ "Vset(x)" == "Vfrom(0,x)"
+
+rules
+ Limit_def "Limit(i) == Ord(i) & 0:i & (ALL y:i. succ(y): i)"
+
+ Vfrom_def "Vfrom(A,i) == transrec(i, %x f. A Un (UN y:x. Pow(f`y)))"
+
+ Vrec_def
+ "Vrec(a,H) == transrec(rank(a), %x g. lam z: Vset(succ(x)). \
+\ H(z, lam w:Vset(x). g`rank(w)`w)) ` a"
+
+ univ_def "univ(A) == Vfrom(A,nat)"
+
+end