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Theorem merlem2 1568
Description: Step 4 of Meredith's proof of Lukasiewicz axioms from his sole axiom. (Contributed by NM, 14-Dec-2002.) (Proof modification is discouraged.) (New usage is discouraged.)
Assertion
Ref Expression
merlem2  |-  ( ( ( ph  ->  ph )  ->  ch )  ->  ( th  ->  ch ) )

Proof of Theorem merlem2
StepHypRef Expression
1 merlem1 1567 . 2  |-  ( ( ( ( ch  ->  ch )  ->  ( -.  ph 
->  -.  th ) )  ->  ph )  ->  ( ph  ->  ph ) )
2 meredith 1566 . 2  |-  ( ( ( ( ( ch 
->  ch )  ->  ( -.  ph  ->  -.  th )
)  ->  ph )  -> 
( ph  ->  ph )
)  ->  ( (
( ph  ->  ph )  ->  ch )  ->  ( th  ->  ch ) ) )
31, 2ax-mp 5 1  |-  ( ( ( ph  ->  ph )  ->  ch )  ->  ( th  ->  ch ) )
Colors of variables: wff setvar class
Syntax hints:   -. wn 3    -> wi 4
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8
This theorem is referenced by:  merlem3  1569  merlem12  1578
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