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Description: Existence of a function expressed as class of ordered pairs. (Contributed by NM, 21-Jul-1996)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | opabex.1 | |- A e. _V |
|
| opabex.2 | |- ( x e. A -> E* y ph ) |
||
| Assertion | opabex | |- { <. x , y >. | ( x e. A /\ ph ) } e. _V |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | opabex.1 | |- A e. _V |
|
| 2 | opabex.2 | |- ( x e. A -> E* y ph ) |
|
| 3 | funopab | |- ( Fun { <. x , y >. | ( x e. A /\ ph ) } <-> A. x E* y ( x e. A /\ ph ) ) |
|
| 4 | moanimv | |- ( E* y ( x e. A /\ ph ) <-> ( x e. A -> E* y ph ) ) |
|
| 5 | 2 4 | mpbir | |- E* y ( x e. A /\ ph ) |
| 6 | 3 5 | mpgbir | |- Fun { <. x , y >. | ( x e. A /\ ph ) } |
| 7 | dmopabss | |- dom { <. x , y >. | ( x e. A /\ ph ) } C_ A |
|
| 8 | 1 7 | ssexi | |- dom { <. x , y >. | ( x e. A /\ ph ) } e. _V |
| 9 | funex | |- ( ( Fun { <. x , y >. | ( x e. A /\ ph ) } /\ dom { <. x , y >. | ( x e. A /\ ph ) } e. _V ) -> { <. x , y >. | ( x e. A /\ ph ) } e. _V ) |
|
| 10 | 6 8 9 | mp2an | |- { <. x , y >. | ( x e. A /\ ph ) } e. _V |