Theorem u2lem1n 740

Description: Lemma for unified implication study. (Contributed by NM, 16-Dec-1997.)

Assertion

Ref	Expression
u2lem1n	((a →2 b) →2 a)⊥ = a⊥

Proof of Theorem u2lem1n

Step	Hyp	Ref	Expression
1		u2lem1 735	. 2 ((a →2 b) →2 a) = a
2	1	ax-r4 37	1 ((a →2 b) →2 a)⊥ = a⊥

Syntax hints:   = wb 1  ^⊥ wn 4   →₂ wi2 13

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

This theorem depends on definitions:  df-a 40  df-t 41  df-f 42  df-i2 45

This theorem is referenced by:  u2lem2  745