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Theorem pm2.64 701
Description: Theorem *2.64 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
Assertion
Ref Expression
pm2.64 ((φ ψ) → ((φ ¬ ψ) → φ))

Proof of Theorem pm2.64
StepHypRef Expression
1 ax-1 5 . . 3 (φ → ((φ ψ) → φ))
2 orel2 632 . . 3 ψ → ((φ ψ) → φ))
31, 2jaoi 623 . 2 ((φ ¬ ψ) → ((φ ψ) → φ))
43com12 27 1 ((φ ψ) → ((φ ¬ ψ) → φ))
Colors of variables: wff set class
Syntax hints:  ¬ wn 3  wi 4   wo 616
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-in2 533  ax-io 617
This theorem depends on definitions:  df-bi 110
This theorem is referenced by: (None)
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