Theorem lem4.6.4 1086

Description: Equation 4.12 of [MegPav2000] p. 23. (Contributed by Roy F. Longton, 1-Jul-2005.)

Assertion

Ref	Expression
lem4.6.4	((a →1 b) →1 b) = (a⊥ →1 b)

Proof of Theorem lem4.6.4

Step	Hyp	Ref	Expression
1		u1lem12 781	1 ((a →1 b) →1 b) = (a⊥ →1 b)

Syntax hints:   = wb 1  ^⊥ wn 4   →₁ wi1 12

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-i1 44  df-le1 130  df-le2 131  df-c1 132  df-c2 133

This theorem is referenced by: (None)