Description: "At most one" is still the case when a conjunct is added. (Contributed by NM, 22-Apr-1995)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | moan | |- ( E* x ph -> E* x ( ps /\ ph ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | simpr | |- ( ( ps /\ ph ) -> ph ) |
|
| 2 | 1 | moimi | |- ( E* x ph -> E* x ( ps /\ ph ) ) |