reserve a,b,i,k,m,n for Nat;
reserve s,z for non zero Nat;
reserve c for Complex;

theorem Th8:
  -1 div 3 = -1
  proof
    (-1) / 3 - 1 < -1;
    then [\ (-1) / 3 /] = -1 by INT_1:def 6;
    hence thesis by INT_1:def 9;
  end;
