Description: Vacuous restricted existential quantification is false. (Contributed by NM, 15-Oct-2003)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | rex0 | |- -. E. x e. (/) ph |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | noel | |- -. x e. (/) |
|
| 2 | 1 | pm2.21i | |- ( x e. (/) -> -. ph ) |
| 3 | 2 | nrex | |- -. E. x e. (/) ph |