Metamath Proof Explorer

Theorem pm5.35

Description: Theorem *5.35 of WhiteheadRussell p. 125. Closed form of 2thd . (Contributed by NM, 3-Jan-2005)

Ref Expression
Assertion pm5.35 ⊢ φ → ψ ∧ φ → χ → φ → ψ ↔ χ

Proof

Step Hyp Ref Expression
1 pm5.1 ⊢ φ → ψ ∧ φ → χ → φ → ψ ↔ φ → χ
2 1 pm5.74rd ⊢ φ → ψ ∧ φ → χ → φ → ψ ↔ χ