reserve x,y,z,X for set,
  T for Universe;

theorem Th13:
  for R be non empty RelStr, T be non empty 1-sorted, p be Element
  of T holds the_value_of (ConstantNet(R,p)) = p
proof
  let R be non empty RelStr, T be non empty 1-sorted, p be Element of T;
  thus the_value_of (ConstantNet(R,p)) = the_value_of the mapping of
  ConstantNet(R,p) by Def8
    .= the_value_of ((the carrier of ConstantNet(R,p)) --> p) by Def5
    .= p by FUNCOP_1:79;
end;
