Metamath Proof Explorer


Theorem f1o0

Description: One-to-one onto mapping of the empty set. (Contributed by NM, 10-Sep-2004)

Ref Expression
Assertion f1o0 ∅ : ∅ –1-1-onto→ ∅

Proof

Step Hyp Ref Expression
1 eqid ∅ = ∅
2 f1o00 ( ∅ : ∅ –1-1-onto→ ∅ ↔ ( ∅ = ∅ ∧ ∅ = ∅ ) )
3 1 1 2 mpbir2an ∅ : ∅ –1-1-onto→ ∅