Theorem falxorfal 1433

Description: A \/_ identity. (Contributed by David A. Wheeler, 2-Mar-2018.)

Assertion

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

Proof of Theorem falxorfal

Step	Hyp	Ref	Expression
1		df-xor 1387	. 2 |- ( ( F. \/_ F. ) <-> ( ( F. \/ F. ) /\ -. ( F. /\ F. ) ) )
2		oridm 758	. . 3 |- ( ( F. \/ F. ) <-> F. )
3		notfal 1425	. . . 4 |- ( -. F. <-> T. )
4		anidm 396	. . . 4 |- ( ( F. /\ F. ) <-> F. )
5	3, 4	xchnxbir 682	. . 3 |- ( -. ( F. /\ F. ) <-> T. )
6	2, 5	anbi12i 460	. 2 |- ( ( ( F. \/ F. ) /\ -. ( F. /\ F. ) ) <-> ( F. /\ T. ) )
7		falantru 1414	. 2 |- ( ( F. /\ T. ) <-> F. )
8	1, 6, 7	3bitri 206	1 |- ( ( F. \/_ F. ) <-> F. )

Syntax hints:   -. wn 3   /\ wa 104   <-> wb 105   \/ wo 709   T. wtru 1365   F. wfal 1369   \/_ wxo 1386

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-io 710

This theorem depends on definitions:  df-bi 117  df-tru 1367  df-fal 1370  df-xor 1387

This theorem is referenced by: (None)