Description: The singleton of a set is not empty. (Contributed by Glauco Siliprandi, 3-Mar-2021)
Ref | Expression | ||
---|---|---|---|
Hypothesis | snn0d.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
Assertion | snn0d | ⊢ ( 𝜑 → { 𝐴 } ≠ ∅ ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | snn0d.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
2 | snnzg | ⊢ ( 𝐴 ∈ 𝑉 → { 𝐴 } ≠ ∅ ) | |
3 | 1 2 | syl | ⊢ ( 𝜑 → { 𝐴 } ≠ ∅ ) |