Metamath Proof Explorer


Theorem relen

Description: Equinumerosity is a relation. (Contributed by NM, 28-Mar-1998)

Ref Expression
Assertion relen Rel ≈

Proof

Step Hyp Ref Expression
1 df-en ≈ = { ⟨ 𝑥 , 𝑦 ⟩ ∣ ∃ 𝑓 𝑓 : 𝑥1-1-onto𝑦 }
2 1 relopabiv Rel ≈