Theorem vtoclef 2984

Description: Implicit substitution of a class for a set variable. (Contributed by NM, 18-Aug-1993.)

Hypotheses

Ref	Expression
vtoclef.1	|- F/ x ph
vtoclef.2	|- A e. _V
vtoclef.3	|- ( x = A -> ph )

Assertion

Ref	Expression
vtoclef	|- ph

Distinct variable group:   x, A

Allowed substitution hint:   ph( x)

Proof of Theorem vtoclef

Step	Hyp	Ref	Expression
1		vtoclef.2	. . 3 |- A e. _V
2	1	isseti 2922	. 2 |- E. x x = A
3		vtoclef.1	. . 3 |- F/ x ph
4		vtoclef.3	. . 3 |- ( x = A -> ph )
5	3, 4	exlimi 1817	. 2 |- ( E. x x = A -> ph )
6	2, 5	ax-mp 8	1 |- ph

Syntax hints:   -> wi 4   E.wex 1547   F/wnf 1550   = wceq 1649   e. wcel 1721   _Vcvv 2916

This theorem is referenced by:  nn0ind-raph  10326

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1552  ax-5 1563  ax-17 1623  ax-9 1662  ax-8 1683  ax-6 1740  ax-11 1757  ax-ext 2385

This theorem depends on definitions:  df-bi 178  df-an 361  df-ex 1548  df-nf 1551  df-sb 1656  df-clab 2391  df-cleq 2397  df-clel 2400  df-v 2918