Description: The domain of a set is a set. (Contributed by Glauco Siliprandi, 26-Jun-2021)
Ref | Expression | ||
---|---|---|---|
Hypothesis | dmexd.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
Assertion | dmexd | ⊢ ( 𝜑 → dom 𝐴 ∈ V ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dmexd.1 | ⊢ ( 𝜑 → 𝐴 ∈ 𝑉 ) | |
2 | dmexg | ⊢ ( 𝐴 ∈ 𝑉 → dom 𝐴 ∈ V ) | |
3 | 1 2 | syl | ⊢ ( 𝜑 → dom 𝐴 ∈ V ) |