an-false<

Theorem.

Arguments:

phi (pr), psi (pr),

Assertions:

(lnotphito(phileftrightarrow(psiwedgephi)))

Proof:

Hyp Ref Line Expr
<neg1(lnotphito(phito(psiwedgephi)))
siman>2((psiwedgephi)tophi)
2ax13(lnotphito((psiwedgephi)tophi))
1, 3>bid4(lnotphito(phileftrightarrow(psiwedgephi)))