reserve G for _Graph;
reserve V for non empty set, E for Relation of V;

theorem Th78:
  for v being Vertex of createGraph(V,E) holds E|{v} = v.edgesOut()
proof
  let v be Vertex of createGraph(V,E);
  thus E|{v} = createGraph(V,E).edgesOutOf({v}) by Th74
    .= v.edgesOut() by GLIB_000:def 39;
end;
