Theorem pm2.6 162

Description: Theorem *2.6 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.6	|- ((-. ph -> ps) -> ((ph -> ps) -> ps))

Proof of Theorem pm2.6

Step	Hyp	Ref	Expression
1		id 19	. 2 |- ((-. ph -> ps) -> (-. ph -> ps))
2		idd 21	. 2 |- ((-. ph -> ps) -> (ps -> ps))
3	1, 2	jad 154	1 |- ((-. ph -> ps) -> ((ph -> ps) -> ps))

Syntax hints:  -. wn 3   -> wi 4

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem is referenced by:  pm2.61  163