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Theorem 19.25 1499
Description: Theorem 19.25 of [Margaris] p. 90. (Contributed by NM, 5-Aug-1993.) (Revised by NM, 2-Feb-2015.)
Assertion
Ref Expression
19.25 (yx(φψ) → (yxφyxψ))

Proof of Theorem 19.25
StepHypRef Expression
1 19.35-1 1497 . . 3 (x(φψ) → (xφxψ))
21alimi 1324 . 2 (yx(φψ) → y(xφxψ))
3 exim 1472 . 2 (y(xφxψ) → (yxφyxψ))
42, 3syl 14 1 (yx(φψ) → (yxφyxψ))
Colors of variables: wff set class
Syntax hints:  wi 4  wal 1226  wex 1362
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101  ax-5 1316  ax-gen 1318  ax-ie1 1363  ax-ie2 1364  ax-4 1381  ax-ial 1409
This theorem depends on definitions:  df-bi 110
This theorem is referenced by: (None)
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