<bsylan>
Theorem.
Arguments:
(pr),
(pr),
(pr),
(pr),
Hypotheses:
(
)
((
)
)
Assertions:
((
)
)
Proof:
Hyp
Ref
Line
Expr
Hypo
1
(
)
2
((
)
)
1
bi<
3
(
)
2, 3
sylan>
4
((
)
)