Description: Operation value of the empty set. (Contributed by AV, 15-May-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | 0ov | |- ( A (/) B ) = (/) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-ov | |- ( A (/) B ) = ( (/) ` <. A , B >. ) |
|
| 2 | 0fv | |- ( (/) ` <. A , B >. ) = (/) |
|
| 3 | 1 2 | eqtri | |- ( A (/) B ) = (/) |