rp-2>d

Theorem.

Arguments:

a (obj), b (obj), c (obj), phi (pr),

Hypotheses:

(phito(beqc))
(phito(aleb))

Assertions:

(phito(alec))

Proof:

Hyp Ref Line Expr
Hypo1(phito(beqc))
2(phito(aleb))
1eqt>3(phito((aleb)leftrightarrow(alec)))
3bi>4(phito((aleb)to(alec)))
2, 4mpd5(phito(alec))