con

Theorem. Contraposition.

Description:

Theorem *2.16 of Principia Mathematica, p. 103; con3 in set.mm.

Arguments:

(pr), (pr),

Assertions:

(()())

Proof:

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