Metamath Proof Explorer


Theorem opelxpi

Description: Ordered pair membership in a Cartesian product (implication). (Contributed by NM, 28-May-1995)

Ref Expression
Assertion opelxpi A C B D A B C × D

Proof

Step Hyp Ref Expression
1 opelxp A B C × D A C B D
2 1 biimpri A C B D A B C × D