src/ZF/Nat.thy

-(*  Title: 	ZF/Nat.thy
+(*  Title:      ZF/Nat.thy
     ID:         $Id$
-    Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
+    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
     Copyright   1994  University of Cambridge
 
 Natural numbers in Zermelo-Fraenkel Set Theory 
 *)
 
 Nat = Ordinal + Bool + "mono" +
 consts
-    nat 	::      i
+    nat         ::      i
     nat_case    ::      [i, i=>i, i]=>i
     nat_rec     ::      [i, i, [i,i]=>i]=>i
 
 defs
 
     nat_def     "nat == lfp(Inf, %X. {0} Un {succ(i). i:X})"
 
     nat_case_def
-	"nat_case(a,b,k) == THE y. k=0 & y=a | (EX x. k=succ(x) & y=b(x))"
+        "nat_case(a,b,k) == THE y. k=0 & y=a | (EX x. k=succ(x) & y=b(x))"
 
     nat_rec_def
-	"nat_rec(k,a,b) ==   
-   	  wfrec(Memrel(nat), k, %n f. nat_case(a, %m. b(m, f`m), n))"
+        "nat_rec(k,a,b) ==   
+          wfrec(Memrel(nat), k, %n f. nat_case(a, %m. b(m, f`m), n))"
 
 end