Metamath Proof Explorer


Theorem brrelex1i

Description: The first argument of a binary relation exists. (An artifact of our ordered pair definition.) (Contributed by NM, 4-Jun-1998)

Ref Expression
Hypothesis brrelexi.1 RelR
Assertion brrelex1i ARBAV

Proof

Step Hyp Ref Expression
1 brrelexi.1 RelR
2 brrelex1 RelRARBAV
3 1 2 mpan ARBAV