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Description: If the domain of a function given by maps-to notation is a class abstraction based on a set, the function is a set. (Contributed by AV, 16-Jul-2019) (Revised by AV, 26-Mar-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | mptrabex.1 | ⊢ 𝐴 ∈ V | |
| Assertion | mptrabex | ⊢ ( 𝑥 ∈ { 𝑦 ∈ 𝐴 ∣ 𝜑 } ↦ 𝐵 ) ∈ V |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | mptrabex.1 | ⊢ 𝐴 ∈ V | |
| 2 | 1 | rabex | ⊢ { 𝑦 ∈ 𝐴 ∣ 𝜑 } ∈ V |
| 3 | 2 | mptex | ⊢ ( 𝑥 ∈ { 𝑦 ∈ 𝐴 ∣ 𝜑 } ↦ 𝐵 ) ∈ V |