Description: Vacuous restricted uniqueness is always false. (Contributed by AV, 3-Apr-2023)
Ref | Expression | ||
---|---|---|---|
Assertion | reu0 | |- -. E! x e. (/) ph |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rex0 | |- -. E. x e. (/) ph |
|
2 | reurex | |- ( E! x e. (/) ph -> E. x e. (/) ph ) |
|
3 | 1 2 | mto | |- -. E! x e. (/) ph |