Theorem ska14 514

Description: Soundness proof for KA14. (Contributed by NM, 3-Nov-1997.)

Assertion

Ref	Expression
ska14	((a⊥ ∪ b) →3 (a →3 (a →3 b))) = 1

Proof of Theorem ska14

Step	Hyp	Ref	Expression
1		lem4 511	. . . 4 (a →3 (a →3 b)) = (a⊥ ∪ b)
2	1	ax-r1 35	. . 3 (a⊥ ∪ b) = (a →3 (a →3 b))
3	2	ri3 253	. 2 ((a⊥ ∪ b) →3 (a →3 (a →3 b))) = ((a →3 (a →3 b)) →3 (a →3 (a →3 b)))
4		i3id 251	. 2 ((a →3 (a →3 b)) →3 (a →3 (a →3 b))) = 1
5	3, 4	ax-r2 36	1 ((a⊥ ∪ b) →3 (a →3 (a →3 b))) = 1

Syntax hints:   = wb 1  ^⊥ wn 4   ∪ wo 6  1wt 8   →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)