reserve d,i,j,k,m,n,p,q,x,k1,k2 for Nat,
  a,c,i1,i2,i3,i5 for Integer;

theorem Th44:
  n <> 0 implies n div n = 1
proof
  assume n <> 0;
  then n*1 div n = 1 by NAT_D:18;
  hence thesis;
end;
