Theorem falxorfal

Description: A \/_ identity. (Contributed by David A. Wheeler, 9-May-2015)

	Ref	Expression
Assertion	falxorfal	|- ( ( F. \/_ F. ) <-> F. )

Proof

Step	Hyp	Ref	Expression
1		df-xor	|- ( ( F. \/_ F. ) <-> -. ( F. <-> F. ) )
2		falbifal	|- ( ( F. <-> F. ) <-> T. )
3	1 2	xchbinx	|- ( ( F. \/_ F. ) <-> -. T. )
4		nottru	|- ( -. T. <-> F. )
5	3 4	bitri	|- ( ( F. \/_ F. ) <-> F. )