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Metamath Proof Explorer

Theorem truimfal

Description: A -> identity. (Contributed by Anthony Hart, 22-Oct-2010) (Proof shortened by Andrew Salmon, 13-May-2011)

Ref Expression
Assertion truimfal ( ( ⊤ → ⊥ ) ↔ ⊥ )

Proof

Step Hyp Ref Expression
1 trut ⊢ ( ⊥ ↔ ( ⊤ → ⊥ ) )
2 1 bicomi ⊢ ( ( ⊤ → ⊥ ) ↔ ⊥ )