bi.bldbi<

Theorem.

Arguments:

phi (pr), psi (pr), chi (pr),

Hypotheses:

(phileftrightarrowpsi)

Assertions:

((phileftrightarrowchi)leftrightarrow(psileftrightarrowchi))

Proof:

Hyp Ref Line Expr
Hypo1(phileftrightarrowpsi)
bicom2((phileftrightarrowchi)leftrightarrow(chileftrightarrowphi))
1bi.bldbi>3((chileftrightarrowphi)leftrightarrow(chileftrightarrowpsi))
bicom4((chileftrightarrowpsi)leftrightarrow(psileftrightarrowchi))
2, 3, 42bitr5((phileftrightarrowchi)leftrightarrow(psileftrightarrowchi))