Theorem sbhyp 1936

Description: Change variable of an implicit substitution hypothesis, introducing an explicit substitution. (Contributed by Raph Levien, 10-Apr-2004.)

Hypothesis

Ref	Expression
sbhyp.1	|- (x = A -> (ph <-> ps))

Assertion

Ref	Expression
sbhyp	|- (y = A -> ([y / x]ph <-> ps))

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

Proof of Theorem sbhyp

Step	Hyp	Ref	Expression
1		visset 1809	. . 3 |- y e. V
2		eqeq1 1478	. . 3 |- (x = y -> (x = A <-> y = A))
3	1, 2	ceqsexv 1831	. 2 |- (E.x(x = y /\ x = A) <-> y = A)
4		hbs1 1330	. . . 4 |- ([y / x]ph -> A.x[y / x]ph)
5		ax-17 969	. . . 4 |- (ps -> A.xps)
6	4, 5	hbbi 1008	. . 3 |- (([y / x]ph <-> ps) -> A.x([y / x]ph <-> ps))
7		sbequ12 1179	. . . . 5 |- (x = y -> (ph <-> [y / x]ph))
8	7	bicomd 520	. . . 4 |- (x = y -> ([y / x]ph <-> ph))
9		sbhyp.1	. . . 4 |- (x = A -> (ph <-> ps))
10	8, 9	sylan9bb 539	. . 3 |- ((x = y /\ x = A) -> ([y / x]ph <-> ps))
11	6, 10	19.23ai 1062	. 2 |- (E.x(x = y /\ x = A) -> ([y / x]ph <-> ps))
12	3, 11	sylbir 201	1 |- (y = A -> ([y / x]ph <-> ps))

Syntax hints:   -> wi 3   <-> wb 146   /\ wa 223   = wceq 954  E.wex 978  [wsbc 1168

This theorem is referenced by:  nn0ind-raph 6170

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 960  ax-gen 961  ax-10 964  ax-12 966  ax-17 969  ax-4 971  ax-5o 973  ax-6o 976  ax-9o 1121  ax-10o 1138  ax-16 1208  ax-11o 1216  ax-ext 1457

This theorem depends on definitions:  df-bi 147  df-an 225  df-ex 979  df-sb 1170  df-clab 1462  df-cleq 1467  df-clel 1470  df-v 1808

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