Description: There does not exist exactly one set such that F. is true. (Contributed by Anthony Hart, 13-Sep-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | neufal | ⊢ ¬ ∃! 𝑥 ⊥ |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nexfal | ⊢ ¬ ∃ 𝑥 ⊥ | |
2 | euex | ⊢ ( ∃! 𝑥 ⊥ → ∃ 𝑥 ⊥ ) | |
3 | 1 2 | mto | ⊢ ¬ ∃! 𝑥 ⊥ |