Theorem pm3.42 543

Description: Theorem *3.42 of [WhiteheadRussell] p. 113. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm3.42	⊢ ((ψ → χ) → ((φ ∧ ψ) → χ))

Proof of Theorem pm3.42

Step	Hyp	Ref	Expression
1		simpr 447	. 2 ⊢ ((φ ∧ ψ) → ψ)
2	1	imim1i 54	1 ⊢ ((ψ → χ) → ((φ ∧ ψ) → χ))

Syntax hints:   → wi 4   ∧ wa 358

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 177  df-an 360

This theorem is referenced by: (None)