Theorem mtand 666

Description: A modus tollens deduction. (Contributed by Jeff Hankins, 19-Aug-2009.)

Hypotheses

Ref	Expression
mtand.1	|- ( ph -> -. ch )
mtand.2	|- ( ( ph /\ ps ) -> ch )

Assertion

Ref	Expression
mtand	|- ( ph -> -. ps )

Proof of Theorem mtand

Step	Hyp	Ref	Expression
1		mtand.1	. 2 |- ( ph -> -. ch )
2		mtand.2	. . 3 |- ( ( ph /\ ps ) -> ch )
3	2	ex 115	. 2 |- ( ph -> ( ps -> ch ) )
4	1, 3	mtod 664	1 |- ( ph -> -. ps )

Syntax hints:   -. wn 3   -> wi 4   /\ wa 104

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia3 108  ax-in1 615  ax-in2 616

This theorem is referenced by:  frirrg  4386  phpm  6935  diffisn  6963  tridc  6969  nnnninfeq  7203  pm54.43  7269  addcanprleml  7698  addcanprlemu  7699  iseqf1olemklt  10607  isprm5lem  12334  pw2dvdseulemle  12360  sqne2sq  12370  pythagtriplem4  12462  pythagtriplem11  12468  pythagtriplem13  12470  ctinfomlemom  12669  rrgnz  13900  lssvancl1  13999  ivthinc  14963  pwle2  15729