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Description: Restricted existential specialization, using implicit substitution. (Contributed by NM, 26-May-1998) (Revised by Mario Carneiro, 11-Oct-2016)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | rspc.1 | |- F/ x ps |
|
| rspc.2 | |- ( x = A -> ( ph <-> ps ) ) |
||
| Assertion | rspce | |- ( ( A e. B /\ ps ) -> E. x e. B ph ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | rspc.1 | |- F/ x ps |
|
| 2 | rspc.2 | |- ( x = A -> ( ph <-> ps ) ) |
|
| 3 | nfcv | |- F/_ x A |
|
| 4 | nfv | |- F/ x A e. B |
|
| 5 | 4 1 | nfan | |- F/ x ( A e. B /\ ps ) |
| 6 | eleq1 | |- ( x = A -> ( x e. B <-> A e. B ) ) |
|
| 7 | 6 2 | anbi12d | |- ( x = A -> ( ( x e. B /\ ph ) <-> ( A e. B /\ ps ) ) ) |
| 8 | 3 5 7 | spcegf | |- ( A e. B -> ( ( A e. B /\ ps ) -> E. x ( x e. B /\ ph ) ) ) |
| 9 | 8 | anabsi5 | |- ( ( A e. B /\ ps ) -> E. x ( x e. B /\ ph ) ) |
| 10 | df-rex | |- ( E. x e. B ph <-> E. x ( x e. B /\ ph ) ) |
|
| 11 | 9 10 | sylibr | |- ( ( A e. B /\ ps ) -> E. x e. B ph ) |