set G1 = G .set (WeightSelector,X);
OrderingSelector in dom G
by Def6;
then
OrderingSelector in (dom G) \/ {WeightSelector}
by XBOOLE_0:def 3;
hence
OrderingSelector in dom (G .set (WeightSelector,X))
by GLIB_000:7; GLIB_010:def 6 (G .set (WeightSelector,X)) . OrderingSelector is Enumeration of (the_Vertices_of (G .set (WeightSelector,X)))
G == G .set (WeightSelector,X)
by GLIB_003:7;
then A1:
the_Vertices_of G = the_Vertices_of (G .set (WeightSelector,X))
by GLIB_000:def 34;
G . OrderingSelector = (G .set (WeightSelector,X)) . OrderingSelector
by GLIB_003:def 1, GLIB_000:9;
hence
(G .set (WeightSelector,X)) . OrderingSelector is Enumeration of (the_Vertices_of (G .set (WeightSelector,X)))
by A1, Def6; verum