Metamath Proof Explorer


Theorem elopabr

Description: Membership in an ordered-pair class abstraction defined by a binary relation. (Contributed by AV, 16-Feb-2021) (Proof shortened by SN, 11-Dec-2024)

Ref Expression
Assertion elopabr ⊢ A ∈ x y | x R y → A ∈ R

Proof

Step Hyp Ref Expression
1 opabss ⊢ x y | x R y ⊆ R
2 1 sseli ⊢ A ∈ x y | x R y → A ∈ R