reserve c,c1,c2 for Cardinal, G,G1,G2 for _Graph, v for Vertex of G;

theorem Th47:
  G is edgeless iff G is 0-Dregular
proof
  thus G is edgeless implies G is 0-Dregular;
  assume G is 0-Dregular;
  then G is 2*0-regular by Th46;
  hence thesis;
end;
