Description: Excluded middle with equality and inequality. (Contributed by NM, 3-Feb-2012) (Proof shortened by Wolf Lammen, 17-Nov-2019)
Ref | Expression | ||
---|---|---|---|
Assertion | exmidne | ⊢ ( 𝐴 = 𝐵 ∨ 𝐴 ≠ 𝐵 ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | neqne | ⊢ ( ¬ 𝐴 = 𝐵 → 𝐴 ≠ 𝐵 ) | |
2 | 1 | orri | ⊢ ( 𝐴 = 𝐵 ∨ 𝐴 ≠ 𝐵 ) |