lcp [Thu, 03 Nov 1994 12:43:42 +0100] rev 692
ZF/InfDatatype/fun_Vcsucc: removed use of PiE
lcp [Thu, 03 Nov 1994 12:39:39 +0100] rev 691
ZF/func: tidied many proofs, using new definition of Pi(A,B)
ZF/func/PiI,PiE: removed
ZF/func/Pi_iff_old: new
ZF/func/Pi_memberD: new; simpler, replaces memberPiE
lcp [Thu, 03 Nov 1994 12:35:41 +0100] rev 690
ZF: NEW DEFINITION OF PI(A,B)
Was Pi(A,B) == {f: Pow(Sigma(A,B)). ALL x:A. EX! y. <x,y>: f}
Now function(r) == ALL x y. <x,y>:r --> (ALL y'. <x,y'>:r --> y=y')
Pi(A,B) == {f: Pow(Sigma(A,B)). A<=domain(f) & function(f)}"
This simplifies many proofs, since (a) the top-level definition has fewer
bound variables (b) the "total" and "function" properties are separated
(c) the awkward EX! quantifier is eliminated.
ZF/ZF.thy/function: new definition