 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 :: Proposition 4 g)
  kappa(X,Y) = kappa(X,X /\ Y) = kappa_1(X,X /\ Y) = kappa_1(X \ Y,X /\ Y)
    by LemmaKap1,LemmaKap2,LemmaKap3;
