reserve X,Y,z,s for set, L,L1,L2,A,B for List of X, x for Element of X,
  O,O1,O2,O3 for Operation of X, a,b,y for Element of X, n,m for Nat;
reserve F,F1,F2 for filtering Operation of X;
reserve i for Element of NAT;
reserve X for ConstructorDB, A for FinSequence of the Constrs of X,
  x for Element of X;
reserve Y for ref-finite ConstructorDB,
  B for FinSequence of the Constrs of Y,
  y for Element of Y;

theorem
  EXACTLY(B) c= EXACTLY+-(B,n,m)
  proof
    EXACTLY(B) = EXACTLY+-(B,0,0) & 0 <= n & 0 <= m by Th69,NAT_1:2;
    hence thesis by Th72;
  end;
