Theorem com4t 79

Description: Commutation of antecedents. Rotate twice. (Contributed by NM, 25-Apr-1994.)

Hypothesis

Ref	Expression
com4.1	|- (ph -> (ps -> (ch -> (th -> ta))))

Assertion

Ref	Expression
com4t	|- (ch -> (th -> (ph -> (ps -> ta))))

Proof of Theorem com4t

Step	Hyp	Ref	Expression
1		com4.1	. . 3 |- (ph -> (ps -> (ch -> (th -> ta))))
2	1	com4l 78	. 2 |- (ps -> (ch -> (th -> (ph -> ta))))
3	2	com4l 78	1 |- (ch -> (th -> (ph -> (ps -> ta))))

This proof depends on syntax axioms:   -> wi 4

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7

This theorem is used by:  com4r  80  com24  81  mopick  2266