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Description: Membership in a restricted class abstraction, using implicit substitution. (Contributed by NM, 21-May-1999) Remove dependency on ax-13 . (Revised by Steven Nguyen, 23-Nov-2022)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | elrab.1 | |- ( x = A -> ( ph <-> ps ) ) |
|
| Assertion | elrab | |- ( A e. { x e. B | ph } <-> ( A e. B /\ ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elrab.1 | |- ( x = A -> ( ph <-> ps ) ) |
|
| 2 | elex | |- ( A e. { x e. B | ph } -> A e. _V ) |
|
| 3 | elex | |- ( A e. B -> A e. _V ) |
|
| 4 | 3 | adantr | |- ( ( A e. B /\ ps ) -> A e. _V ) |
| 5 | eleq1 | |- ( x = A -> ( x e. B <-> A e. B ) ) |
|
| 6 | 5 1 | anbi12d | |- ( x = A -> ( ( x e. B /\ ph ) <-> ( A e. B /\ ps ) ) ) |
| 7 | df-rab | |- { x e. B | ph } = { x | ( x e. B /\ ph ) } |
|
| 8 | 6 7 | elab2g | |- ( A e. _V -> ( A e. { x e. B | ph } <-> ( A e. B /\ ps ) ) ) |
| 9 | 2 4 8 | pm5.21nii | |- ( A e. { x e. B | ph } <-> ( A e. B /\ ps ) ) |