Theorem intn3an2d 10424

Description: Introduction of a conjunct inside a contradiction.

Hypothesis

Ref	Expression
intn3and.1	|- (ph -> -. ps)

Assertion

Ref	Expression
intn3an2d	|- (ph -> -. (ch /\ ps /\ th))

Proof of Theorem intn3an2d

Step	Hyp	Ref	Expression
1		intn3and.1	. . . 4 |- (ph -> -. ps)
2	1	intnand 695	. . 3 |- (ph -> -. (ch /\ ps))
3	2	intnanrd 696	. 2 |- (ph -> -. ((ch /\ ps) /\ th))
4		df-3an 779	. . 3 |- ((ch /\ ps /\ th) <-> ((ch /\ ps) /\ th))
5	4	negbii 187	. 2 |- (-. (ch /\ ps /\ th) <-> -. ((ch /\ ps) /\ th))
6	3, 5	sylibr 200	1 |- (ph -> -. (ch /\ ps /\ th))

Syntax hints:  -. wn 2   -> wi 3   /\ wa 223   /\ w3a 777

This theorem is referenced by:  iintlem1 10603

This theorem was proved from axioms:  ax-1 4  ax-2 5  ax-3 6  ax-mp 7

This theorem depends on definitions:  df-bi 147  df-an 225  df-3an 779

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