Theorem cbvalvw 1968

Description: Change bound variable. See cbvalv 1966 for a version with fewer disjoint variable conditions. (Contributed by NM, 9-Apr-2017.) Avoid ax-7 1497. (Revised by GG, 25-Aug-2024.)

Hypothesis

Ref	Expression
cbvalvw.1	|- ( x = y -> ( ph <-> ps ) )

Assertion

Ref	Expression
cbvalvw	|- ( A. x ph <-> A. y ps )

Distinct variable groups:   x, y   ps, x   ph, y

Allowed substitution hints:   ph( x)   ps( y)

Proof of Theorem cbvalvw

Step	Hyp	Ref	Expression
1		cbvalvw.1	. . . 4 |- ( x = y -> ( ph <-> ps ) )
2	1	spv 1908	. . 3 |- ( A. x ph -> ps )
3	2	alrimiv 1922	. 2 |- ( A. x ph -> A. y ps )
4	1	equcoms 1756	. . . . 5 |- ( y = x -> ( ph <-> ps ) )
5	4	biimprd 158	. . . 4 |- ( y = x -> ( ps -> ph ) )
6	5	spimv 1859	. . 3 |- ( A. y ps -> ph )
7	6	alrimiv 1922	. 2 |- ( A. y ps -> A. x ph )
8	3, 7	impbii 126	1 |- ( A. x ph <-> A. y ps )

Syntax hints:   -> wi 4   <-> wb 105   A.wal 1396

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 1496  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583

This theorem depends on definitions:  df-bi 117  df-nf 1510

This theorem is referenced by:  cbvaldvaw  1979  cbval2vw  1981  cbvralvw  2772  cbvreuvw  2774