Description: Deduction rule for nonempty classes. (Contributed by Thierry Arnoux, 3-Aug-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | n0limd.1 | |- ( ph -> A =/= (/) ) |
|
| n0limd.2 | |- ( ( ph /\ x e. A ) -> ps ) |
||
| Assertion | n0limd | |- ( ph -> ps ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | n0limd.1 | |- ( ph -> A =/= (/) ) |
|
| 2 | n0limd.2 | |- ( ( ph /\ x e. A ) -> ps ) |
|
| 3 | n0 | |- ( A =/= (/) <-> E. x x e. A ) |
|
| 4 | 1 3 | sylib | |- ( ph -> E. x x e. A ) |
| 5 | 4 2 | exlimddv | |- ( ph -> ps ) |