Description: Definition of the truth value "false", or "falsum", denoted by F. . See also df-tru . (Contributed by Anthony Hart, 22-Oct-2010)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-fal | |- ( F. <-> -. T. ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | wfal | |- F. |
|
| 1 | wtru | |- T. |
|
| 2 | 1 | wn | |- -. T. |
| 3 | 0 2 | wb | |- ( F. <-> -. T. ) |