\documentclass[a4paper]{article} \begin{document} \title{The Numerical Solution of a Neumann Problem\\ for Parabolic Singular Perturbed Equations\\ with High-Order Time Accuracy} \thanks{This research was supported in part by the Dutch Research Organisation NWO under grant N 047.003.017 and by the Russian Foundation for Basic Research under grant N 98-01-00362.}} \author{P.W.~Hemker\thanks{ CWI, Amsterdam, The Netherlands.} \and \ G.I.~Shishkin\thanks{ Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Science, Ekaterinburg, Russia.} \and \ L.P.~Shishkina\thanks{ Scientific Research Institute of Heavy Machine Building, Ekaterinburg, Russia.} } \maketitle We study the discrete approximation of a Neumann problem on an interval for a singularly perturbed parabolic PDE. For this boundary value problem we construct a special piecewise-uniform mesh on which the discretisation, based on the classical finite difference approximation, converges $\epsilon$-uniformly with the order ${\cal O} (N^{-2}\ln^2 N+K^{-1})$, where, respectively, $N$ and $K$ are the number of intervals in the space and the time mesh. With such discretisations we construct schemes of high order accuracy in the time. To obtain the better accuracy, we use a defect correction technique. Auxiliary discrete problems on the same time-mesh are introduced to correct the low order difference approximations. To validate the theoretical results, some numerical results for the new schemes are presented. \end{document}