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 φψχθ
Assertion biimp3a φψχθ

Proof

Step Hyp Ref Expression
1 biimp3a.1 φψχθ
2 1 biimpa φψχθ
3 2 3impa φψχθ