Q. lim lim_(x→a y→b) A_(m,n) =L Suppose a double sequence A_(m,n) converges to L. According to the Moore-Osgood Theorem the order of limits can be interchanged if at least one direction converges uniformly. I find this counterintuitve I don′t understand why uniform convergence in just one direction is sufficient to guarantee the validity of switching the limits. It would be much easier to accept if uniform convergence were required in both directions.