bi.bldan<>

Theorem.

Arguments:

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

Hypotheses:

(chileftrightarrowtheta)
(phileftrightarrowpsi)

Assertions:

((phiwedgechi)leftrightarrow(psiwedgetheta))

Proof:

Hyp Ref Line Expr
Hypo1(chileftrightarrowtheta)
2(phileftrightarrowpsi)
2bi.bldan<3((phiwedgechi)leftrightarrow(psiwedgechi))
1bi.bldan>4((psiwedgechi)leftrightarrow(psiwedgetheta))
3, 4bitr5((phiwedgechi)leftrightarrow(psiwedgetheta))