reserve r,s,t,u for Real;
reserve V for RealLinearSpace,
  v,w for Point of V;

theorem Th72:
 v in Line(v,w)
proof
  v = (1-0)*v + 0.V by RLVECT_1:def 8
    .= (1-0)*v + 0*w by RLVECT_1:10;
 hence thesis;
end;
