<neg

Theorem. From a wff and its negation, anything is true.

Description:

Theorem *2.21 of Principia Mathematica, p. 104; pm2.21 in set.mm. Also called the Duns Scotus law.

Arguments:

(pr), (pr),

Assertions:

(())

Proof:

Hyp	Ref	Line	Expr
	ax1	1	(())
1	ax3	2	(())