2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/491The aim of this paper is to clarify the notion and cause of overmerging in N-body simulations, and to present analytical estimates for its timescale. Overmerging is the disruption of subhaloes within embedding haloes due to {\it numerical} problems connected with the discreteness of N-body dynamics. It is shown that the process responsible for overmerging is particle-subhalo two-body heating. Various solutions to the overmerging problem are discussed4 pages, 1 figure, submitted to Monthly NoticesAstrophysicstext