“…However, very little attention has so far been paid to the studies of preservation of solution nonnegativity and boundedness in the discretization of Nagumo-type equations. The existing work includes [7,32,39,41] where only finite difference discretization and isotropic diffusion have been considered. On the other hand, preservation of solution nonnegativity and boundedness has important physical implications and has attracted considerable attention from researchers in the recent years [7,14,15,16,28,29,31,38,43,46,47].…”