reserve a,b,c,d,m,x,n,j,k,l for Nat,
  t,u,v,z for Integer,
  f,F for FinSequence of NAT;
reserve p,q,r,s for real number;

theorem Th18:
  t-z divides t|^m - z|^m
  proof
    (t-z) divides ((t-z)+z)|^n iff (t-z) divides z|^n by Th11;
    hence thesis by Th10;
  end;
