reserve x for object,
  a,b for Real,
  k,k1,i1,j1,w for Nat,
  m,m1,n,n1 for Integer;
reserve p,q for Rational;

theorem Th8:
  1 <= denominator(p)
proof
  0+1<=denominator(p) by NAT_1:13;
  hence thesis;
end;
