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Description: If the domain of a mapping is a set, the function is a set. (Contributed by Glauco Siliprandi, 26-Jun-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | fexd.1 | ⊢ ( 𝜑 → 𝐹 : 𝐴 ⟶ 𝐵 ) | |
| fexd.2 | ⊢ ( 𝜑 → 𝐴 ∈ 𝐶 ) | ||
| Assertion | fexd | ⊢ ( 𝜑 → 𝐹 ∈ V ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fexd.1 | ⊢ ( 𝜑 → 𝐹 : 𝐴 ⟶ 𝐵 ) | |
| 2 | fexd.2 | ⊢ ( 𝜑 → 𝐴 ∈ 𝐶 ) | |
| 3 | fex | ⊢ ( ( 𝐹 : 𝐴 ⟶ 𝐵 ∧ 𝐴 ∈ 𝐶 ) → 𝐹 ∈ V ) | |
| 4 | 1 2 3 | syl2anc | ⊢ ( 𝜑 → 𝐹 ∈ V ) |