Abstract:
The Dirichlet problem for a parabolic reaction-diffusion equation is considered on a segment. The highest derivative of the equation is multiplied by a parameter $\varepsilon$ taking
arbitrary values in the half-interval (0,1]. For this problem we consider classical difference
approximations of the equations on sequentially locally refined (a posteriori) meshes. On
the subdomains subjected to refining, which are defined by the gradients of the mesh
solutions of the intermediate problems, uniform meshes are used. We construct special
schemes which allow us to obtain the approximations that converge "almost $\varepsilon$-uniformly",i.e., with an error weakly depending on $\varepsilon\colon |u(x,t)-z(x,t)|\le M[N_1^{-2/3}+\varepsilon ^{-\nu}N_1^{-1}+N_0^{-1}]$,
$(x,t)\in\overline G_h$, where $\nu$ is an arbitrary number from (0,1]; $N_1+1$ and $N_0+1$ are the number of the mesh nodes in $x$ and $t$.