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Description: The empty binary relation never holds. (Contributed by NM, 23-Aug-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | br0 | ⊢ ¬ 𝐴 ∅ 𝐵 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | noel | ⊢ ¬ 〈 𝐴 , 𝐵 〉 ∈ ∅ | |
| 2 | df-br | ⊢ ( 𝐴 ∅ 𝐵 ↔ 〈 𝐴 , 𝐵 〉 ∈ ∅ ) | |
| 3 | 1 2 | mtbir | ⊢ ¬ 𝐴 ∅ 𝐵 |