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Theorem nsyld 587
Description: A negated syllogism deduction. (Contributed by NM, 9-Apr-2005.)
Hypotheses
Ref Expression
nsyld.1  |-  ( ph  ->  ( ps  ->  -.  ch ) )
nsyld.2  |-  ( ph  ->  ( ta  ->  ch ) )
Assertion
Ref Expression
nsyld  |-  ( ph  ->  ( ps  ->  -.  ta ) )

Proof of Theorem nsyld
StepHypRef Expression
1 nsyld.1 . 2  |-  ( ph  ->  ( ps  ->  -.  ch ) )
2 nsyld.2 . . 3  |-  ( ph  ->  ( ta  ->  ch ) )
32con3d 571 . 2  |-  ( ph  ->  ( -.  ch  ->  -. 
ta ) )
41, 3syld 44 1  |-  ( ph  ->  ( ps  ->  -.  ta ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-in1 554  ax-in2 555
This theorem is referenced by:  pm2.65d  596  fzdcel  9006
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