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Theorem exp4d 351
Description: An exportation inference. (Contributed by NM, 26-Apr-1994.)
Hypothesis
Ref Expression
exp4d.1 (φ → ((ψ (χ θ)) → τ))
Assertion
Ref Expression
exp4d (φ → (ψ → (χ → (θτ))))

Proof of Theorem exp4d
StepHypRef Expression
1 exp4d.1 . . 3 (φ → ((ψ (χ θ)) → τ))
21expd 245 . 2 (φ → (ψ → ((χ θ) → τ)))
32exp4a 348 1 (φ → (ψ → (χ → (θτ))))
Colors of variables: wff set class
Syntax hints:  wi 4   wa 97
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 99  ax-ia2 100  ax-ia3 101
This theorem depends on definitions:  df-bi 110
This theorem is referenced by:  tfrlem9  5876
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