Theorem cbvalvw 1907

Description: Change bound variable. See cbvalv 1905 for a version with fewer disjoint variable conditions. (Contributed by NM, 9-Apr-2017.) Avoid ax-7 1436. (Revised by Gino Giotto, 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 1848	. . 3 |- ( A. x ph -> ps )
3	2	alrimiv 1862	. 2 |- ( A. x ph -> A. y ps )
4	1	equcoms 1696	. . . . 5 |- ( y = x -> ( ph <-> ps ) )
5	4	biimprd 157	. . . 4 |- ( y = x -> ( ps -> ph ) )
6	5	spimv 1799	. . 3 |- ( A. y ps -> ph )
7	6	alrimiv 1862	. 2 |- ( A. y ps -> A. x ph )
8	3, 7	impbii 125	1 |- ( A. x ph <-> A. y ps )

Syntax hints:   -> wi 4   <-> wb 104   A.wal 1341

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-5 1435  ax-gen 1437  ax-ie1 1481  ax-ie2 1482  ax-8 1492  ax-4 1498  ax-17 1514  ax-i9 1518  ax-ial 1522

This theorem depends on definitions:  df-bi 116  df-nf 1449

This theorem is referenced by:  cbvralvw  2696  cbvreuvw  2698