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Metamath Proof Explorer

Theorem funtopon

Description: The class TopOn is a function. (Contributed by BJ, 29-Apr-2021)

Ref Expression
Assertion funtopon Fun TopOn

Proof

Step Hyp Ref Expression
1 df-topon ⊢ TopOn = ( 𝑦 ∈ V ↦ { 𝑥 ∈ Top ∣ 𝑦 = ∪ 𝑥 } )
2 1 funmpt2 ⊢ Fun TopOn