Theorem chvar 1680

Description: Implicit substitution of y for x into a theorem. (Contributed by Raph Levien, 9-Jul-2003.) (Revised by Mario Carneiro, 3-Oct-2016.)

Hypotheses

Ref	Expression
chvar.1	|- F/ x ps
chvar.2	|- ( x = y -> ( ph <-> ps ) )
chvar.3	|- ph

Assertion

Ref	Expression
chvar	|- ps

Proof of Theorem chvar

Step	Hyp	Ref	Expression
1		chvar.1	. . 3 |- F/ x ps
2		chvar.2	. . . 4 |- ( x = y -> ( ph <-> ps ) )
3	2	biimpd 142	. . 3 |- ( x = y -> ( ph -> ps ) )
4	1, 3	spim 1666	. 2 |- ( A. x ph -> ps )
5		chvar.3	. 2 |- ph
6	4, 5	mpg 1380	1 |- ps

Syntax hints:   -> wi 4   <-> wb 103   F/wnf 1389

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-5 1376  ax-gen 1378  ax-ie1 1422  ax-ie2 1423  ax-4 1440  ax-i9 1463  ax-ial 1467

This theorem depends on definitions:  df-bi 115  df-nf 1390

This theorem is referenced by:  csbhypf  2941  opelopabsb  4015  findes  4344  fvmptssdm  5276  dfoprab4f  5839  dom2lem  6275  uzind4s  8678