Theorem a4w 929

Description: A weaker version of a4c 843.

Hypothesis

Ref	Expression
a4w.1	|- (x = y -> (ph -> ps))

Assertion

Ref	Expression
a4w	|- (ph -> E.xps)

Distinct variable group(s):   ph,x

Proof of Theorem a4w

Step	Hyp	Ref	Expression
1		ax-17 925	. 2 |- (ph -> A.xph)
2		a4w.1	. 2 |- (x = y -> (ph -> ps))
3	1, 2	a4c 843	1 |- (ph -> E.xps)

Syntax hints:   -> wi 2  E.wex 678   = weq 797

This theorem is referenced by:  a4w1 930  zfpair 1891

This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673  ax-5 674  ax-6 675  ax-gen 677  ax-9 799  ax-17 925

This theorem depends on definitions:  df-bi 128  df-an 198  df-ex 679

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