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Description: The empty binary relation never holds. (Contributed by NM, 23-Aug-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | br0 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | noel | ||
| 2 | df-br | ||
| 3 | 1 2 | mtbir |