bi.bldim<>

Theorem.

Arguments:

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

Hypotheses:

(chileftrightarrowtheta)
(phileftrightarrowpsi)

Assertions:

((phitochi)leftrightarrow(psitotheta))

Proof:

Hyp Ref Line Expr
Hypo1(chileftrightarrowtheta)
2(phileftrightarrowpsi)
2bi.bldim<3((phitochi)leftrightarrow(psitochi))
1bi.bldim>4((psitochi)leftrightarrow(psitotheta))
3, 4bitr5((phitochi)leftrightarrow(psitotheta))