The first boundary-value problem for strongly elliptic functional-differential equations with orthotropic contractions

We obtain a number of necessary and sufficient strong ellipticity conditions for a functional-differential equation containing, in its leading part, orthotropic contractions of the argument of the unknown function. We establish the unique solvability of the first boundary-value problem and the discreteness, semiboundedness, and sectorial structure of its spectrum. © 2015, Pleiades Publishing, Ltd