theorem :: GLIB_006:152

for G2 being _finite _Graph
for v1 being Vertex of G2
for e, v2 being object
for G1 being addAdjVertex of G2,v1,e,v2 st not e in the_Edges_of G2 & not v2 in the_Vertices_of G2 holds
( G1 .order() = (G2 .order()) + 1 & G1 .size() = (G2 .size()) + 1 )