Metamath Proof Explorer


Theorem opvtxov

Description: The set of vertices of a graph represented as an ordered pair of vertices and indexed edges as operation value. (Contributed by AV, 21-Sep-2020)

Ref Expression
Assertion opvtxov
|- ( ( V e. X /\ E e. Y ) -> ( V Vtx E ) = V )

Proof

Step Hyp Ref Expression
1 df-ov
 |-  ( V Vtx E ) = ( Vtx ` <. V , E >. )
2 opvtxfv
 |-  ( ( V e. X /\ E e. Y ) -> ( Vtx ` <. V , E >. ) = V )
3 1 2 syl5eq
 |-  ( ( V e. X /\ E e. Y ) -> ( V Vtx E ) = V )