Theorem oaeqv 812

Description: Weakened OA implies OA).

Hypothesis

Ref	Expression
oaeqv.1	((a →2 b) ∩ ((b ∪ c)⊥ ∪ ((a →2 b) ∩ (a →2 c)))) ≤ ((b ∪ c) →2 ((a →2 b) ∩ (a →2 c)))

Assertion

Ref	Expression
oaeqv	((a →2 b) ∩ ((b ∪ c)⊥ ∪ ((a →2 b) ∩ (a →2 c)))) ≤ (a →2 c)

Proof of Theorem oaeqv

Step	Hyp	Ref	Expression
1		lea 152	. . . 4 ((a →2 b) ∩ ((b ∪ c)⊥ ∪ ((a →2 b) ∩ (a →2 c)))) ≤ (a →2 b)
2		oaeqv.1	. . . 4 ((a →2 b) ∩ ((b ∪ c)⊥ ∪ ((a →2 b) ∩ (a →2 c)))) ≤ ((b ∪ c) →2 ((a →2 b) ∩ (a →2 c)))
3	1, 2	ler2an 165	. . 3 ((a →2 b) ∩ ((b ∪ c)⊥ ∪ ((a →2 b) ∩ (a →2 c)))) ≤ ((a →2 b) ∩ ((b ∪ c) →2 ((a →2 b) ∩ (a →2 c))))
4		2oath1 808	. . 3 ((a →2 b) ∩ ((b ∪ c) →2 ((a →2 b) ∩ (a →2 c)))) = ((a →2 b) ∩ (a →2 c))
5	3, 4	lbtr 131	. 2 ((a →2 b) ∩ ((b ∪ c)⊥ ∪ ((a →2 b) ∩ (a →2 c)))) ≤ ((a →2 b) ∩ (a →2 c))
6		lear 153	. 2 ((a →2 b) ∩ (a →2 c)) ≤ (a →2 c)
7	5, 6	letr 129	1 ((a →2 b) ∩ ((b ∪ c)⊥ ∪ ((a →2 b) ∩ (a →2 c)))) ≤ (a →2 c)

Syntax hints:   ≤ wle 2  ^⊥ wn 4   ∪ wo 6   ∩ wa 7   →₂ wi2 14

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  ax-r3 421

This theorem depends on definitions:  df-b 38  df-a 39  df-t 40  df-f 41  df-i2 44  df-le1 122  df-le2 123  df-c1 124  df-c2 125

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