Metamath Proof Explorer


Theorem aibandbiaiffaiffb

Description: A closed form showing (a implies b and b implies a) same-as (a same-as b). (Contributed by Jarvin Udandy, 3-Sep-2016)

Ref Expression
Assertion aibandbiaiffaiffb φ ψ ψ φ φ ψ

Proof

Step Hyp Ref Expression
1 dfbi2 φ ψ φ ψ ψ φ
2 1 bicomi φ ψ ψ φ φ ψ