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Theorem pm2.65d 166
Description: Deduction rule for proof by contradiction. (Contributed by NM, 26-Jun-1994.) (Proof shortened by Wolf Lammen, 26-May-2013.)
Hypotheses
Ref Expression
pm2.65d.1
pm2.65d.2
Assertion
Ref Expression
pm2.65d

Proof of Theorem pm2.65d
StepHypRef Expression
1 pm2.65d.2 . . 3
2 pm2.65d.1 . . 3
31, 2nsyld 132 . 2
43pm2.01d 161 1
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:  mtod  168  pm2.65da  559
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