Theorem chvar 1779

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 144	. . 3 |- ( x = y -> ( ph -> ps ) )
4	1, 3	spim 1760	. 2 |- ( A. x ph -> ps )
5		chvar.3	. 2 |- ph
6	4, 5	mpg 1473	1 |- ps

Syntax hints:   -> wi 4   <-> wb 105   F/wnf 1482

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1469  ax-gen 1471  ax-ie1 1515  ax-ie2 1516  ax-4 1532  ax-i9 1552  ax-ial 1556

This theorem depends on definitions:  df-bi 117  df-nf 1483

This theorem is referenced by:  csbhypf  3131  opelopabsb  4305  findes  4650  fvmptssdm  5663  dfoprab4f  6278  dom2lem  6862  uzind4s  9710  fsumsplitf  11690