Metamath Proof Explorer

Theorem anbi2i

Description: Introduce a left conjunct to both sides of a logical equivalence. (Contributed by NM, 3-Jan-1993) (Proof shortened by Wolf Lammen, 16-Nov-2013)

Ref Expression
Hypothesis anbi.1 φ ψ
Assertion anbi2i χ φ χ ψ


Step Hyp Ref Expression
1 anbi.1 φ ψ
2 1 a1i χ φ ψ
3 2 pm5.32i χ φ χ ψ