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Considering the generalized Bessel functions satisfying a special ordinary differential equation of mth order, we derive some addition theorems and generating functions with the help of some algebra constructed for a group of first order partial differential operators grounding on the recurrence relations for these functions.

We introduce a system of exponential functions with shift, study its basis properties in L2, and examine its connections with the Kostyuchenko problem.

The question of the preservation of discreteness of the spectrum of the Laplacian acting in a space of differential forms under the cutting and gluing of manifolds reduces to the same problem for compact solvability of the operator of exterior derivation. Along these lines, we give some conditions on a cut Y dividing a Riemannian manifold X into two parts X+ and X− under which the spectrum of the Laplacian on X is discrete if and only if so are the spectra of the Laplacians on X+ and X−.

We obtain an integral formula for a solution to a general algebraic equation. In this formula the integrand is an elementary function and integration is carried out over an interval. The advantage of this formula over the well-known Mellin formula is that the integral has a broader convergence domain. This circumstance makes it possible to describe the monodromy of a solution for trinomial equations.