Description: "At most one" exports disjunction to conjunction. (Contributed by NM, 5-Apr-2004) (Proof shortened by Andrew Salmon, 9-Jul-2011)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | mooran2 | |- ( E* x ( ph \/ ps ) -> ( E* x ph /\ E* x ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | moor | |- ( E* x ( ph \/ ps ) -> E* x ph ) |
|
| 2 | olc | |- ( ps -> ( ph \/ ps ) ) |
|
| 3 | 2 | moimi | |- ( E* x ( ph \/ ps ) -> E* x ps ) |
| 4 | 1 3 | jca | |- ( E* x ( ph \/ ps ) -> ( E* x ph /\ E* x ps ) ) |