The nonlocal boundary problem with perturbations of antiperiodicity conditions for the eliptic equation with constant coefficients
Journal Title: Карпатські математичні публікації - Year 2018, Vol 10, Issue 2
Abstract
In this article, we investigate a problem with nonlocal boundary conditions which are perturbations of antiperiodical conditions in bounded m-dimensional parallelepiped using Fourier method. We describe properties of a transformation operator R:L2(G)→L2(G), which gives us a connection between selfadjoint operator L0 of the problem with antiperiodical conditions and operator L of perturbation of the nonlocal problem RL0=LR. Also we construct a commutative group of transformation operators Γ(L0). We show that some abstract nonlocal problem corresponds to any transformation operator R∈Γ(L0):L2(G)→L2(G) and vice versa. We construct a system V(L) of root functions of operator L, which consists of infinite number of adjoint functions. Also we define conditions under which the system V(L) is total and minimal in the space L2(G), and conditions under which it is a Riesz basis in the space L2(G). In case if V(L) is a Riesz basis in the space L2(G), we obtain sufficient conditions under which the nonlocal problem has a unique solution in the form of Fourier series by system V(L).
Authors and Affiliations
Ya. Baranetskij, I. Ivasiuk, P. Kalenyuk, A. V. Solomko
Generalized types of the growth of Dirichlet series
Let A∈(−∞,+∞] and Φ be a continuously on [σ0,A) function such that Φ(σ)→+∞ as σ→A−0. We establish a necessary and sufficient condition on a nonnegative sequence λ=(λn), increasing to +∞, under which the equality ¯¯¯¯¯¯¯¯...
Poincare series for the algebras of joint invariants and covariants of n quadratic forms
We consider one of the fundamental objects of classical invariant theory, namely the Poincare series for an algebra of invariants of Lie group $SL_2$. The first two terms of the Laurent series expansion of Poincar\'e se...
Boundary problem for the singular heat equation
The scheme for solving of a mixed problem with general boundary conditions is proposed for a heat equation $$ a(x)\frac{\partial T}{\partial \tau}= \frac{\partial}{\partial x} \left(\lambda(x)\frac{\partial T}{\partial x...
A Worpitzky boundary theorem for branched continued fractions of the special form
For a branched continued fraction of a special form we propose the limit value set for the Worpitzky-like theorem when the element set of the branched continued fraction is replaced by its boundary.
Superextensions of three-element semigroups
A family $\mathcal{A}$ of non-empty subsets of a set $X$ is called an {\em upfamily} if for each set $A\in\mathcal{A}$ any set $B\supset A$ belongs to $\mathcal{A}$. An upfamily $\mathcal L$ of subsets of $X$ is said to...