Description: Membership in a domain. Theorem 4 of Suppes p. 59. (Contributed by NM, 1-Aug-1994)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | eldm.1 | |- A e. _V | |
| Assertion | eldm2 | |- ( A e. dom B <-> E. y <. A , y >. e. B ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | eldm.1 | |- A e. _V | |
| 2 | eldm2g | |- ( A e. _V -> ( A e. dom B <-> E. y <. A , y >. e. B ) ) | |
| 3 | 1 2 | ax-mp | |- ( A e. dom B <-> E. y <. A , y >. e. B ) |