Theorem wlem1 235

Description: Lemma for 2-variable WOML proof.

Assertion

Ref	Expression
wlem1	((a == b)_|_ v ((a ->1 b) ^ (b ->1 a))) = 1

Proof of Theorem wlem1

Step	Hyp	Ref	Expression
1		le1 138	. 2 ((a == b)_|_ v ((a ->1 b) ^ (b ->1 a))) =< 1
2		df-t 40	. . . 4 1 = ((a == b) v (a == b)_|_)
3		ax-a2 30	. . . 4 ((a == b) v (a == b)_|_) = ((a == b)_|_ v (a == b))
4	2, 3	ax-r2 35	. . 3 1 = ((a == b)_|_ v (a == b))
5		dfb 86	. . . . 5 (a == b) = ((a ^ b) v (a_|_ ^ b_|_))
6		ledio 168	. . . . . 6 ((a ^ b) v (a_|_ ^ b_|_)) =< (((a ^ b) v a_|_) ^ ((a ^ b) v b_|_))
7		df-i1 43	. . . . . . . . 9 (a ->1 b) = (a_|_ v (a ^ b))
8		ax-a2 30	. . . . . . . . 9 (a_|_ v (a ^ b)) = ((a ^ b) v a_|_)
9	7, 8	ax-r2 35	. . . . . . . 8 (a ->1 b) = ((a ^ b) v a_|_)
10		df-i1 43	. . . . . . . . 9 (b ->1 a) = (b_|_ v (b ^ a))
11		ax-a2 30	. . . . . . . . . 10 (b_|_ v (b ^ a)) = ((b ^ a) v b_|_)
12		ancom 68	. . . . . . . . . . 11 (b ^ a) = (a ^ b)
13	12	ax-r5 37	. . . . . . . . . 10 ((b ^ a) v b_|_) = ((a ^ b) v b_|_)
14	11, 13	ax-r2 35	. . . . . . . . 9 (b_|_ v (b ^ a)) = ((a ^ b) v b_|_)
15	10, 14	ax-r2 35	. . . . . . . 8 (b ->1 a) = ((a ^ b) v b_|_)
16	9, 15	2an 72	. . . . . . 7 ((a ->1 b) ^ (b ->1 a)) = (((a ^ b) v a_|_) ^ ((a ^ b) v b_|_))
17	16	ax-r1 34	. . . . . 6 (((a ^ b) v a_|_) ^ ((a ^ b) v b_|_)) = ((a ->1 b) ^ (b ->1 a))
18	6, 17	lbtr 131	. . . . 5 ((a ^ b) v (a_|_ ^ b_|_)) =< ((a ->1 b) ^ (b ->1 a))
19	5, 18	bltr 130	. . . 4 (a == b) =< ((a ->1 b) ^ (b ->1 a))
20	19	lelor 158	. . 3 ((a == b)_|_ v (a == b)) =< ((a == b)_|_ v ((a ->1 b) ^ (b ->1 a)))
21	4, 20	bltr 130	. 2 1 =< ((a == b)_|_ v ((a ->1 b) ^ (b ->1 a)))
22	1, 21	lebi 137	1 ((a == b)_|_ v ((a ->1 b) ^ (b ->1 a))) = 1

Syntax hints:   = wb 1  _|_wn 4   == tb 5   v wo 6   ^ wa 7  1wt 9   ->1 wi1 13

This theorem is referenced by:  wr5-2v 348

This theorem was proved from axioms:  ax-a1 29  ax-a2 30  ax-a3 31  ax-a4 32  ax-a5 33  ax-r1 34  ax-r2 35  ax-r4 36  ax-r5 37

This theorem depends on definitions:  df-b 38  df-a 39  df-t 40  df-f 41  df-i1 43  df-le1 122  df-le2 123

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