Theorem 2ax17 1667

Description: Quantification of two variables over a formula in which they do not occur. (Contributed by Alan Sare, 12-Apr-2011.)

Assertion

Ref	Expression
2ax17	|- (ph -> A.xA.yph)

Distinct variable groups:   ph,x   ph,y

Proof of Theorem 2ax17

Step	Hyp	Ref	Expression
1		id 73	. 2 |- (ph -> ph)
2	1	19.21aivv 1665	1 |- (ph -> A.xA.yph)

Syntax hints:   -> wi 3  A.wal 1296

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-mp 7  ax-gen 1305  ax-17 1317  ax-4 1319  ax-5o 1321

Copyright terms: Public domain