Metamath Proof Explorer


Theorem mofal

Description: There exist at most one set such that F. is true. (Contributed by Anthony Hart, 13-Sep-2011)

Ref Expression
Assertion mofal ∃* 𝑥 ⊥

Proof

Step Hyp Ref Expression
1 nexfal ⊢ ¬ ∃ 𝑥 ⊥
2 exmo ⊢ ( ∃ 𝑥 ⊥ ∨ ∃* 𝑥 ⊥ )
3 1 2 mtpor ⊢ ∃* 𝑥 ⊥