“…Boundary value problems similar to Carleman's problem, with the boundary condition relating the values of the unknown function at different points on the boundary were considered (see monograph of Antonevich, Belousov and Lebedev [1] and the references cited there). Finiteness theorems were proved and for the case of finite group actions index theorems were obtained (see also [48]). On the other hand, nonlocal boundary value problems, in which the boundary condition relates the values of a function on the boundary of the domain and on submanifolds, which lie inside the domain there were considered in [15,[62][63][64].…”