Theorem cbv3ALT 1526

Description: Rule used to change bound variables, using implicit substitition. (The proof was shortened by Andrew Salmon, 25-May-2011.)

Hypotheses

Ref	Expression
cbv3.1	|- (ph -> A.yph)
cbv3.2	|- (ps -> A.xps)
cbv3.3	|- (x = y -> (ph -> ps))

Assertion

Ref	Expression
cbv3ALT	|- (A.xph -> A.yps)

Proof of Theorem cbv3ALT

Step	Hyp	Ref	Expression
1		cbv3.1	. . . 4 |- (ph -> A.yph)
2	1	a1i 8	. . 3 |- (y = y -> (ph -> A.yph))
3		cbv3.2	. . . 4 |- (ps -> A.xps)
4	3	a1i 8	. . 3 |- (y = y -> (ps -> A.xps))
5		cbv3.3	. . . 4 |- (x = y -> (ph -> ps))
6	5	a1i 8	. . 3 |- (y = y -> (x = y -> (ph -> ps)))
7	2, 4, 6	cbv1 1523	. 2 |- (A.xA.y y = y -> (A.xph -> A.yps))
8		stdpc6 1486	. 2 |- A.y y = y
9	7, 8	mpg 1332	1 |- (A.xph -> A.yps)

Syntax hints:   -> wi 3  A.wal 1296   = wceq 1298

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7  ax-7 1304  ax-gen 1305  ax-12 1310  ax-4 1319  ax-5o 1321  ax-6o 1324  ax-9o 1481

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