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Mirrors > Home > MPE Home > Th. List > Mathboxes > frege27 | Structured version Visualization version Unicode version |
Description: We cannot (at the same time) affirm and deny . Identical to id 22. Proposition 27 of [Frege1879] p. 43. (Contributed by RP, 24-Dec-2019.) (Proof modification is discouraged.) |
Ref | Expression |
---|---|
frege27 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax-frege1 38084 | . 2 | |
2 | frege26 38104 | . 2 | |
3 | 1, 2 | ax-mp 5 | 1 |
Colors of variables: wff setvar class |
Syntax hints: wi 4 |
This theorem was proved from axioms: ax-mp 5 ax-frege1 38084 ax-frege8 38103 |
This theorem is referenced by: frege42 38140 |
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