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Mirrors > Home > ILE Home > Th. List > Mathboxes > nnexmid | Unicode version |
Description: Double negation of excluded middle. Intuitionistic logic refutes the negation of excluded middle (but, of course, does not prove excluded middle) for any formula. (Contributed by BJ, 9-Oct-2019.) |
Ref | Expression |
---|---|
nnexmid |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | pm3.24 627 | . 2 | |
2 | ioran 669 | . 2 | |
3 | 1, 2 | mtbir 596 | 1 |
Colors of variables: wff set class |
Syntax hints: wn 3 wa 97 wo 629 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 99 ax-ia2 100 ax-ia3 101 ax-in1 544 ax-in2 545 ax-io 630 |
This theorem depends on definitions: df-bi 110 |
This theorem is referenced by: nndc 9900 |
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