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Metamath Proof Explorer


Theorem biimp3a

Description: Infer implication from a logical equivalence. Similar to biimpa . (Contributed by NM, 4-Sep-2005)

Ref Expression
Hypothesis biimp3a.1 φ ψ χ θ
Assertion biimp3a φ ψ χ θ

Proof

Step Hyp Ref Expression
1 biimp3a.1 φ ψ χ θ
2 1 biimpa φ ψ χ θ
3 2 3impa φ ψ χ θ