Description: A -/\ identity. (Contributed by Anthony Hart, 23-Oct-2010) (Proof shortened by Andrew Salmon, 13-May-2011)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | falnantru | ⊢ ( ( ⊥ ⊼ ⊤ ) ↔ ⊤ ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | nancom | ⊢ ( ( ⊥ ⊼ ⊤ ) ↔ ( ⊤ ⊼ ⊥ ) ) | |
| 2 | trunanfal | ⊢ ( ( ⊤ ⊼ ⊥ ) ↔ ⊤ ) | |
| 3 | 1 2 | bitri | ⊢ ( ( ⊥ ⊼ ⊤ ) ↔ ⊤ ) |