Metamath Proof Explorer


Theorem oprab4

Description: Two ways to state the domain of an operation. (Contributed by FL, 24-Jan-2010)

Ref Expression
Assertion oprab4 x y z | x y A × B φ = x y z | x A y B φ

Proof

Step Hyp Ref Expression
1 opelxp x y A × B x A y B
2 1 anbi1i x y A × B φ x A y B φ
3 2 oprabbii x y z | x y A × B φ = x y z | x A y B φ