<2bitr<

Theorem.

Arguments:

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

Hypotheses:

(thetaleftrightarrowpsi)
(chileftrightarrowphi)
(phileftrightarrowpsi)

Assertions:

(thetaleftrightarrowchi)

Proof:

Hyp Ref Line Expr
Hypo1(thetaleftrightarrowpsi)
2(chileftrightarrowphi)
3(phileftrightarrowpsi)
1, 2, 3<2bitr4(chileftrightarrowtheta)
4bicomi5(thetaleftrightarrowchi)