Theorem i3orlem7 558

Description: Lemma for Kalmbach implication OR builder. (Contributed by NM, 11-Nov-1997.)

Assertion

Ref	Expression
i3orlem7	(a ∩ b⊥ ) ≤ ((a →3 b)⊥ ∪ ((a ∪ c) →3 (b ∪ c)))

Proof of Theorem i3orlem7

Step	Hyp	Ref	Expression
1		lea 160	. . . . . . 7 (a ∩ b⊥ ) ≤ a
2		leo 158	. . . . . . 7 a ≤ (a ∪ b)
3	1, 2	letr 137	. . . . . 6 (a ∩ b⊥ ) ≤ (a ∪ b)
4		leo 158	. . . . . 6 (a ∩ b⊥ ) ≤ ((a ∩ b⊥ ) ∪ (a ∩ b))
5	3, 4	ler2an 173	. . . . 5 (a ∩ b⊥ ) ≤ ((a ∪ b) ∩ ((a ∩ b⊥ ) ∪ (a ∩ b)))
6	5	ler 149	. . . 4 (a ∩ b⊥ ) ≤ (((a ∪ b) ∩ ((a ∩ b⊥ ) ∪ (a ∩ b))) ∪ ((a ∪ b) ∩ (a⊥ ∩ (a ∪ b⊥ ))))
7		i3n1 249	. . . . . . 7 (a⊥ →3 b⊥ ) = (((a ∩ b⊥ ) ∪ (a ∩ b)) ∪ (a⊥ ∩ (a ∪ b⊥ )))
8	7	lan 77	. . . . . 6 ((a ∪ b) ∩ (a⊥ →3 b⊥ )) = ((a ∪ b) ∩ (((a ∩ b⊥ ) ∪ (a ∩ b)) ∪ (a⊥ ∩ (a ∪ b⊥ ))))
9		comor1 461	. . . . . . . . 9 (a ∪ b) C a
10		comor2 462	. . . . . . . . . 10 (a ∪ b) C b
11	10	comcom2 183	. . . . . . . . 9 (a ∪ b) C b⊥
12	9, 11	com2an 484	. . . . . . . 8 (a ∪ b) C (a ∩ b⊥ )
13	9, 10	com2an 484	. . . . . . . 8 (a ∪ b) C (a ∩ b)
14	12, 13	com2or 483	. . . . . . 7 (a ∪ b) C ((a ∩ b⊥ ) ∪ (a ∩ b))
15	9	comcom2 183	. . . . . . . 8 (a ∪ b) C a⊥
16	9, 11	com2or 483	. . . . . . . 8 (a ∪ b) C (a ∪ b⊥ )
17	15, 16	com2an 484	. . . . . . 7 (a ∪ b) C (a⊥ ∩ (a ∪ b⊥ ))
18	14, 17	fh1 469	. . . . . 6 ((a ∪ b) ∩ (((a ∩ b⊥ ) ∪ (a ∩ b)) ∪ (a⊥ ∩ (a ∪ b⊥ )))) = (((a ∪ b) ∩ ((a ∩ b⊥ ) ∪ (a ∩ b))) ∪ ((a ∪ b) ∩ (a⊥ ∩ (a ∪ b⊥ ))))
19	8, 18	ax-r2 36	. . . . 5 ((a ∪ b) ∩ (a⊥ →3 b⊥ )) = (((a ∪ b) ∩ ((a ∩ b⊥ ) ∪ (a ∩ b))) ∪ ((a ∪ b) ∩ (a⊥ ∩ (a ∪ b⊥ ))))
20	19	ax-r1 35	. . . 4 (((a ∪ b) ∩ ((a ∩ b⊥ ) ∪ (a ∩ b))) ∪ ((a ∪ b) ∩ (a⊥ ∩ (a ∪ b⊥ )))) = ((a ∪ b) ∩ (a⊥ →3 b⊥ ))
21	6, 20	lbtr 139	. . 3 (a ∩ b⊥ ) ≤ ((a ∪ b) ∩ (a⊥ →3 b⊥ ))
22	21	ler 149	. 2 (a ∩ b⊥ ) ≤ (((a ∪ b) ∩ (a⊥ →3 b⊥ )) ∪ ((a ∪ c) →3 (b ∪ c)))
23		i3orlem6 557	. . 3 ((a →3 b)⊥ ∪ ((a ∪ c) →3 (b ∪ c))) = (((a ∪ b) ∩ (a⊥ →3 b⊥ )) ∪ ((a ∪ c) →3 (b ∪ c)))
24	23	ax-r1 35	. 2 (((a ∪ b) ∩ (a⊥ →3 b⊥ )) ∪ ((a ∪ c) →3 (b ∪ c))) = ((a →3 b)⊥ ∪ ((a ∪ c) →3 (b ∪ c)))
25	22, 24	lbtr 139	1 (a ∩ b⊥ ) ≤ ((a →3 b)⊥ ∪ ((a ∪ c) →3 (b ∪ c)))

Syntax hints:   ≤ wle 2  ^⊥ wn 4   ∪ wo 6   ∩ wa 7   →₃ wi3 14

This theorem was proved from axioms:  ax-a1 30  ax-a2 31  ax-a3 32  ax-a4 33  ax-a5 34  ax-r1 35  ax-r2 36  ax-r4 37  ax-r5 38  ax-r3 439

This theorem depends on definitions:  df-b 39  df-a 40  df-t 41  df-f 42  df-i3 46  df-le1 130  df-le2 131  df-c1 132  df-c2 133

This theorem is referenced by: (None)