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Theorem 3orel13 24086
Description: Elimination of two disjuncts in a triple disjunction. (Contributed by Scott Fenton, 9-Jun-2011.)
Assertion
Ref Expression
3orel13  |-  ( ( -.  ph  /\  -.  ch )  ->  ( ( ph  \/  ps  \/  ch )  ->  ps ) )

Proof of Theorem 3orel13
StepHypRef Expression
1 3orel3 24078 . 2  |-  ( -. 
ch  ->  ( ( ph  \/  ps  \/  ch )  ->  ( ph  \/  ps ) ) )
2 orel1 371 . 2  |-  ( -. 
ph  ->  ( ( ph  \/  ps )  ->  ps ) )
31, 2sylan9r 639 1  |-  ( ( -.  ph  /\  -.  ch )  ->  ( ( ph  \/  ps  \/  ch )  ->  ps ) )
Colors of variables: wff set class
Syntax hints:   -. wn 3    -> wi 4    \/ wo 357    /\ wa 358    \/ w3o 933
This theorem is referenced by:  soseq  24325  nodenselem8  24413
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8
This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-3or 935
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