Metamath Proof Explorer

Theorem pm4.71rd

Description: Deduction converting an implication to a biconditional with conjunction. Deduction from Theorem *4.71 of WhiteheadRussell p. 120. (Contributed by NM, 10-Feb-2005)

Ref Expression
Hypothesis pm4.71rd.1 φ ψ χ
Assertion pm4.71rd φ ψ χ ψ


Step Hyp Ref Expression
1 pm4.71rd.1 φ ψ χ
2 1 pm4.71d φ ψ ψ χ
3 2 biancomd φ ψ χ ψ