Lobachevskii Journal of Mathematics

Propose a cutting-plane method with partially embedding of a feasible set for solving a conditional minimization problem. The proposed method is characterized by possibility of periodically dropping of an arbitrary number of any planes constructed in the solution process. Prove convergence of the method, discuss its features, represent assessments of the solution’s accuracy.

Trong bài báo này, chúng tôi xem xét vấn đề đảo ngược của phương trình tích phân, một vấn đề tự nhiên phát sinh trong lý thuyết các phép đo được sinh ra bởi mật độ cờ (flag densities). Chúng tôi giải quyết phương trình này bằng các phương pháp hình học tích phân và đề xuất một công thức đảo ngược cho mật độ của phép đo trong không gian mặt phẳng dựa trên mật độ cờ của nó.

We consider Riemann–Hilbert boundary value problem with infinite index in unit disk. Its coefficient is Hölder-continuous everywhere on the unit circle excluding a finite set of points, where its argument has power discontinuities of order less one. The present article is the first research of this version of Hilbert boundary-value problem with infinite index. We obtain formulas for its general solution, investigate existence ad uniqueness of solutions, and describe the set of solutions in the case of non-uniqueness. Our technique is based on theory of entire functions and geometric theory of functions.

In this paper for a class of model partial integro-differential equation with super singularity in the kernels, is obtained an integral representation of manifold solutions by arbitrary constants. The conjugate equation for the above-mentioned type of equations is also investigated. Such types of integro-differential equations are different from Cauchy-type singular integro-differential equations. Cauchy-type singular integro-differential equations are studied by the methods of theory of analytical functions. However, the method of analytical functions is not applicable for our case of super singular equations with integrals understanding in Riemann–Stieltjes sense. Here, we have used the method of representation the considering equation as a product of two one-dimensional singular first order integro-differential operators. Further, a complete integro-differential equation and its conjugate equation have been investigated. It is shown that in every cases of characteristic equation roots the homogeneous integro-differential equation can have a nontrivial solutions. Non-model equation is investigated by the regularization method. Regularization of non-model equation is based on selecting a model part of equation. On the basis of the analysis of a model part of equation the solution of non-model equation reduced to the solution of a second kind Volterra integral equations with super singular kernel. It is important to emphasize that in contrast to the usual theory of Volterra integral equations, the studied homogeneous integral equation has nontrivial solutions. It is easy to see that the presence of a non-model part in the equation does not affect to the general structure of the obtained solutions. From here investigation of the model equations for given class of the integro-differential equations becomes important.

Finding a marked vertex in a graph can be a complicated task when using quantum walks. Recent results show that for two or more adjacent marked vertices search by quantum walk with Grover’s coin may have no speed-up over classical exhaustive search. In this paper, we analyze the probability of finding a marked vertex for a set of connected components of marked vertices. We prove two upper bounds on the probability of finding a marked vertex and sketch further research directions.

In this paper, we prove that the dependent bootstrap random variables possess the negative association property.

The first boundary value problem for a second–order differential operator with a singular potential on a segment with conjugation conditions at an interior point of the segment is studied. For the solution of the problem with a parameter, asymptotic formulae and estimates are obtained on each of the segments of smoothness. A similar formula is obtained for the solution of the associated problem.