Preserving stability implicit Euler method for nonlinear Volterra and neutral functional differential equations in Banach space

This paper is concerned with the contractivity and asymptotic stability properties of the implicit Euler method (IEM) for nonlinear functional differential equations (FDEs). These properties are first analyzed for Volterra FDEs and then the analysis is extended to the case of neutral FDEs (NFDEs). Such an extension is particularly important since NFDEs are more general and have received little attention in the literature. The main result we establish is that the IEM with linear interpolation can completely preserve these stability properties of the analytical solution to such FDEs.