con>

Theorem. Contraposition.

Description:

Theorem *2.03 of Principia Mathematica, p. 100; con2 in set.mm.

Arguments:

(pr), (pr),

Assertions:

(()())

Proof:

Hyp	Ref	Line	Expr
	neg<	1	()
1	syl>	2	(()())
2	ax3	3	(()())