let G1 be addEdge of G,v,e,w; :: thesis: G1 is vertex-finite
per cases ( ( v in the_Vertices_of G & w in the_Vertices_of G & not e in the_Edges_of G ) or not v in the_Vertices_of G or not w in the_Vertices_of G or e in the_Edges_of G ) ;
end;