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Theorem a7s 1735
Description: Swap quantifiers in an antecedent. (Contributed by NM, 5-Aug-1993.)
Hypothesis
Ref Expression
a7s.1 (xyφψ)
Assertion
Ref Expression
a7s (yxφψ)

Proof of Theorem a7s
StepHypRef Expression
1 ax-7 1734 . 2 (yxφxyφ)
2 a7s.1 . 2 (xyφψ)
31, 2syl 15 1 (yxφψ)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wal 1540
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-7 1734
This theorem is referenced by:  cbv3hv  1850  cbv3hvOLD  1851  cbv1h  1978  cbv2h  1980  sb9i  2094  ax10-16  2190
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