 reserve R for 1-sorted;
 reserve X,Y for Subset of R;
 reserve R for finite 1-sorted;
 reserve X,Y for Subset of R;
 reserve R for finite Approximation_Space;
 reserve X,Y,Z,W for Subset of R;

theorem Lemma3:
  kappa_2 ({}R,X) = 1
proof
  {}R c= X;
  hence thesis by Prop11b;
end;
