Description: A binary relation does not contain the empty set. (Contributed by AV, 15-Nov-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 0nelrel | |- ( Rel R -> (/) e/ R ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0nelrel0 | |- ( Rel R -> -. (/) e. R ) |
|
| 2 | df-nel | |- ( (/) e/ R <-> -. (/) e. R ) |
|
| 3 | 1 2 | sylibr | |- ( Rel R -> (/) e/ R ) |