 reserve x for Real,
    p,k,l,m,n,s,h,i,j,k1,t,t1 for Nat,
    X for Subset of REAL;

theorem Th14:
  for i being natural Number holds i < 1 implies i = 0
proof
  let i be natural Number;
  assume i < 1;
  then i < 0 + 1;
  then i <= 0 by Th13;
  hence thesis by Th2;
end;
