4orass

Theorem.

Arguments:

(pr), (pr), (pr), (pr),

Assertions:

((()())(()()))

Proof:

Hyp	Ref	Line	Expr
	or12ass	1	((())(()))
1	bi.bldor>	2	(((()))((())))
	orass	3	((()())((())))
	orass	4	((()())((())))
2, 3, 4	<2bitr	5	((()())(()()))