bicomi

Theorem.

Arguments:

phi (pr), psi (pr),

Hypotheses:

(phileftrightarrowpsi)

Assertions:

(psileftrightarrowphi)

Proof:

Hyp Ref Line Expr
Hypo1(phileftrightarrowpsi)
1bi>2(phitopsi)
1bi<3(psitophi)
2, 3>bii4(psileftrightarrowphi)