Metamath Proof Explorer


Theorem zfrep3cl

Description: An inference based on the Axiom of Replacement. Typically, ph defines a function from x to y . (Contributed by NM, 26-Nov-1995)

Ref Expression
Hypotheses zfrep3cl.1
|- A e. _V
zfrep3cl.2
|- ( x e. A -> E. z A. y ( ph -> y = z ) )
Assertion zfrep3cl
|- E. z A. y ( y e. z <-> E. x ( x e. A /\ ph ) )

Proof

Step Hyp Ref Expression
1 zfrep3cl.1
 |-  A e. _V
2 zfrep3cl.2
 |-  ( x e. A -> E. z A. y ( ph -> y = z ) )
3 nfcv
 |-  F/_ x A
4 3 1 2 zfrepclf
 |-  E. z A. y ( y e. z <-> E. x ( x e. A /\ ph ) )