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Description: A restriction to the empty set is empty. (Contributed by NM, 12-Nov-1994)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | res0 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-res | ||
| 2 | 0xp | ||
| 3 | 2 | ineq2i | |
| 4 | in0 | ||
| 5 | 1 3 4 | 3eqtri |