Description: The membership relation is nonempty. (Contributed by AV, 19-Jun-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | epn0 | |- _E =/= (/) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | 0sn0ep |  |-  (/) _E { (/) } | |
| 2 | brne0 |  |-  ( (/) _E { (/) } -> _E =/= (/) ) | |
| 3 | 1 2 | ax-mp | |- _E =/= (/) |