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Theorem pm1.4 645
Description: Axiom *1.4 of [WhiteheadRussell] p. 96. (Contributed by NM, 3-Jan-2005.) (Revised by NM, 15-Nov-2012.)
Assertion
Ref Expression
pm1.4 ((φ ψ) → (ψ φ))

Proof of Theorem pm1.4
StepHypRef Expression
1 olc 631 . 2 (φ → (ψ φ))
2 orc 632 . 2 (ψ → (ψ φ))
31, 2jaoi 635 1 ((φ ψ) → (ψ φ))
Colors of variables: wff set class
Syntax hints:  wi 4   wo 628
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-io 629
This theorem depends on definitions:  df-bi 110
This theorem is referenced by:  orcom  646  orcoms  648  pm2.3  691  pm2.36  716  pm2.37  717  pm2.8  722  dveeq2or  1694  prneimg  3536
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