Description: Membership in a restricted class abstraction, using implicit substitution. (Contributed by NM, 2-Nov-2006)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | elrab2.1 | |- ( x = A -> ( ph <-> ps ) ) |
|
| elrab2.2 | |- C = { x e. B | ph } |
||
| Assertion | elrab2 | |- ( A e. C <-> ( A e. B /\ ps ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elrab2.1 | |- ( x = A -> ( ph <-> ps ) ) |
|
| 2 | elrab2.2 | |- C = { x e. B | ph } |
|
| 3 | 2 | eleq2i | |- ( A e. C <-> A e. { x e. B | ph } ) |
| 4 | 1 | elrab | |- ( A e. { x e. B | ph } <-> ( A e. B /\ ps ) ) |
| 5 | 3 4 | bitri | |- ( A e. C <-> ( A e. B /\ ps ) ) |