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Mirrors > Home > MPE Home > Th. List > nbn2 | Structured version Visualization version Unicode version |
Description: The negation of a wff is equivalent to the wff's equivalence to falsehood. (Contributed by Juha Arpiainen, 19-Jan-2006.) (Proof shortened by Wolf Lammen, 28-Jan-2013.) |
Ref | Expression |
---|---|
nbn2 |
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Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm5.501 347 |
. 2
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2 | notbi 301 |
. 2
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3 | 1, 2 | syl6bbr 271 |
1
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Colors of variables: wff setvar class |
Syntax hints: ![]() ![]() ![]() |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
This theorem depends on definitions: df-bi 190 |
This theorem is referenced by: bibif 352 pm5.21im 355 pm5.18 362 biass 365 sadadd2lem2 14473 isclo 20152 |
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