Theorem sylsyld 57

Description: A double syllogism inference. (Contributed by Alan Sare, 20-Apr-2011.)

Hypotheses

Ref	Expression
sylsyld.1	|- ( ph -> ps )
sylsyld.2	|- ( ph -> ( ch -> th ) )
sylsyld.3	|- ( ps -> ( th -> ta ) )

Assertion

Ref	Expression
sylsyld	|- ( ph -> ( ch -> ta ) )

Proof of Theorem sylsyld

Step	Hyp	Ref	Expression
1		sylsyld.2	. 2 |- ( ph -> ( ch -> th ) )
2		sylsyld.1	. . 3 |- ( ph -> ps )
3		sylsyld.3	. . 3 |- ( ps -> ( th -> ta ) )
4	2, 3	syl 14	. 2 |- ( ph -> ( th -> ta ) )
5	1, 4	syld 44	1 |- ( ph -> ( ch -> ta ) )

Syntax hints:   -> wi 4

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

This theorem is referenced by:  ax10o  1650  a16g  1792  trintssm  3952  funimaexglem  5097  smoiun  6066  findcard2  6605  ltexprlemrl  7169  archsr  7327  elfz0ubfz0  9536