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| Mirrors > Home > ILE Home > Th. List > df-fal | GIF version | ||
| Description: Definition of the truth value "false", or "falsum", denoted by ⊥. See also df-tru 1367. (Contributed by Anthony Hart, 22-Oct-2010.) | 
| Ref | Expression | 
|---|---|
| df-fal | ⊢ (⊥ ↔ ¬ ⊤) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | wfal 1369 | . 2 wff ⊥ | |
| 2 | wtru 1365 | . . 3 wff ⊤ | |
| 3 | 2 | wn 3 | . 2 wff ¬ ⊤ | 
| 4 | 1, 3 | wb 105 | 1 wff (⊥ ↔ ¬ ⊤) | 
| Colors of variables: wff set class | 
| This definition is referenced by: fal 1371 nottru 1424 bdfal 15479 | 
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