Publications

We consider the regularized 3D Navier-Stokes-Cahn-Hilliard equations describing isothermal flows of viscous compressible two-component fluids with interphase effects. We construct for them a new energy dissipative finite-difference discretization in space, i.e., with the non-increasing total energy in time. This property is preserved in the absence of a regularization. In addition, the discretization is well-balanced for equilibrium flows and the potential body force. The sought total density, mixture velocity and concentration of one of the components are defined at nodes of one and the same grid. The results of computer simulation of several 2D test problems are presented. They demonstrate advantages of the constructed discretization including the absence of the so-called parasitic currents.

Bachet’s game is a variant of the game of Nim. There are 𝑛 objects in one pile. Two players take turns to remove any positive number of objects not exceeding some fixed number 𝑚. The player who takes the last object loses. We consider a variant of Bachet’s game in which each move is a lottery over set {1, 2, . . . ,𝑚}. The outcome of a lottery is the number of objects that player takes from the pile. We show that under some nondegenericity assumptions on the set of available lotteries the probability that the first player wins in subgame perfect Nash equilibrium converges to 1/2 as 𝑛 tends to infinity.

What characteristics of firms give them the confidence to invest in settings rife with expropriation by local officials? Empirically, firms in the developing world often face the threat of expropriation from local agents of the state rather than a centralized autocrat. Because policing local officials is costly, the state cannot easily credibly commit to doing so. This has negative consequences for investment. We argue that one solution is to allow firms to approach the state directly to ask for intervention. Not all firms are equally able to successfully get the attention of the state, however, so this mechanism only works for some. We develop an argument about the firm-level characteristics – large-scale employment, political connections, foreign ownership, and business association membership – that should make the central state more attentive to calls for help. Because firm with these characteristics are more likely to secure intervention against predatory bureaucrats, the latter are less likely to try to expropriate them. These firms’ investment decisions should be less sensitive to local expropriation than other firms. We test this argument using data on cases of decentralized expropriation across Russia’s regions and firm-level data from a cross-regional, large scale survey of Russian firms.

It is an important feature of a monotone measure that it is not additive in general. In the paper, we propose the mathematical tool, based on canonical sequences of monotone measures, for analyzing additivity of monotone measures on subalgebras and give a way of generating such monotone measures. It turns out that the generating rule can be considered as an effect of a linear operator defined on the set of monotone measures. We also investigate in what cases the sequence of such operators behaves commutatively and preserve continuity properties from the generating monotone measure.

Researchers have long tried to define the impact of corporate diversification on firm value. Academic papers mainly concentrate on the effects of corporate diversification in mature markets while its consequences in emerging capital markets are less explored. This article presents the results of an empirical analysis of corporate diversification strategies of a sample of companies from BRIC countries that expanded via acquisitions during 2000–2013. We contribute to the existing literature by examining the effects of corporate diversification on firm value during the pre- and post-crisis periods. In line with other studies, we distinguish between related and unrelated diversification and in contrast to them we single out and separately analyze horizontal, conglomerate and vertical acquisitions. Based on a sample of 319 deals initiated by companies from BRIC countries, we found positive (3.32% and 9.01%) and statistically significant cumulative abnormal returns for conglomerate acquisitions during the pre- and post-crisis periods, correspondingly. We also found that the market reacts positively and statistically significant to the announcements of horizontal and vertical integration only during the pre-crisis period.

In recent years corporate international diversification has become a widely used growth strategy for companies from both developed and emerging markets. Nevertheless, academic papers provide contradictory results on whether the influence of international diversification on firm performance is positive or negative. This chapter presents the results of an empirical analysis of corporate international diversification – performance relationship on a sample of companies from BRIC countries, which expanded geographically in 2005-2015. We contribute to the existing literature by applying a new methodology to identify the performance effects of corporate international diversification based on an economic profit measure. The results indicate that there is a non-linear relationship between the degree of international diversification and economics profit spread. Additionally, for BRIC companies international diversification on average does not have a significant impact on expected long term performance, measured by Tobin’s Q.  

Usually DEA methods are used for the assessment of the regions disaster vulnerability. However, most of these methods work with precise values of all the characteristics of the regions. At the same time, in real life, quite often most of the data consists of expert estimates or approximate values. In this regard, we propose to use modified DEA methods, which will take into account inaccuracy of the data. We apply these methods to the evaluation of wildfire preventive measures in regions of the Russian Federation.

The transition from a short-term cost-plus tariff regulation to either a long-term rate-of-return or long-term price cap regulation in Russia started in 2009 and was completed in 2012, causing substantial changes in investment over the course of the reform. We estimate panel data of 46 Russian electricity distribution entities with a dynamic investment model using the system generalized method of moments and addressing potential endogeneity issues. We show that, despite the noncredible regulatory policy, the transition from short-to long-term regulation had a positive and significant effect on the investment rate of regulated entities. The specific long-term regulation design applied in Russia from 2008 to 2017 (either rate-of-return or price cap) had no effect on the investment rate. These results are important for the introduction of changes in regulatory frameworks in developing countries.

We investigate alcohol consumption as one of the main factors contributing to variation in the gender gap in life expectancy in the Russian regions. We consider the socioeconomic indicators and mortality coefficients that enable us to capture the causes of death related primarily to alcohol abuse and smoking. We assume that macroeconomic situation, coupled with alcohol consumption are substantial determinants of the gender gap in life expectancy in the Russian regions. A panel data analysis confirms that alcohol consumption has a significant influence on the gender gap in life expectancy and reduces the life expectancy of men first and foremost, as they are more inclined toward unhealthy behaviours. We have determined that employment and income support policies should be conducted in conjunction with the anti-alcohol policy. Social policy aimed at reducing alcohol consumption should be vigorously reinforced during an economic recovery.

The debate on the increasing income and wealth inequalities in the USA and some other advanced economies often disregards the opposite trend, i.e. decreasing income inequalities between individuals throughout the entire world. The purpose of this chapter is to examine the potential trade-off between both trends and the role of globalisation in such a trade-off. Another important question relates to the impact of this trade-off on global governance. On the one hand, catch-up growth in emerging-market economies and the resulting decrease in global inequality can help reduce the economic and social sources of political conflicts and tensions between countries and enable their cooperation on various issues such as trade, environment, climate change, health, fighting terrorism, managing migration and many others. On the other hand, growing income inequalities within advanced economies can undermine the existing global political and economic order and boost protectionism and nationalistic egoism in many areas.

This chapter surveys the recent trends in the literature on the performance of M&A deals in developed and emerging capital markets. This literature is voluminous, diverse and challenging. We focus on the transactions within one country – domestic M&As – in particular focusing on the methods that the researchers use to estimate whether M&A deals promote efficiency gains or not. We discuss the research instruments which allow an assessment of the effects of M&As on firm operating performance and on firm value. Analysing the results of latest empirical studies we reveal that target shareholders gain significantly in M&A deals. The evidence suggests that in most cases acquiring shareholders receive negative or insignificant returns in the short-run in developed capital markets, while in emerging economies acquiring shareholders mostly gain in M&A deals. Operating performance analysis reveals mixed results in developed and emerging capital markets, while the analysis of papers which use value performance indicators show the destruction of company value due to M&As in developed and emerging capital markets. The review also analyses studies that examine the relationship between different methods.

We consider an application of long-range interaction centrality (LRIC) to the problem of the influence assessment in the global retail food network. Firstly, we reconstruct an initial graph into the graph of directed intensities based on individual nodes characteristics and possibility of the group influence. Secondly, we apply different models of the indirect influence estimation based on simple paths and random walks. This approach can help us to estimate node-to-node influence in networks. Finally, we aggregate node-to-node inifuence into the influence index. The model is applied to the food trade network based on World International Trade Solution database. The results that obtained for the global trade by different product commodities are compared with classical centrality measures.

Using the SIPRI Arms Transfers Database covering all trade in military equipment over the period 1950–2018, we examine the relationship between countries from a novel empirical perspective. We consider the arms transfers network as a multiplex network where each layer corresponds to a particular armament category. First, we analyze how different layers overlap and elucidate main ties between countries. Second, we consider different patterns of trade in order to identify countries specializing on particular armament categories and analyze how they change their export structure in dynamic. We also examine how countries influence each other at different layers of multiplex network. Finally, we analyze the influence of countries in the whole network.

In the last decades of the 20th century, various classes of alternative investments have become increasingly popular among investors. During this time, art as a form of alternative investment attracted attention not only from potential buyers but also from academic scholars. Unfortunately, only a few of the newly published papers contained any quantitative analysis with regard to art’s investment performance. Besides, even a smaller amount of research was devoted to the analysis of Russian art markets. Therefore, the purpose of this work is to evaluate the efficiency of investments in the artworks of contemporary Russian painters and to compare the effectiveness of these investments with the effectiveness of investments in stock, bond and real estate markets in Russia and the USA. For this research, we first conduct a hedonic regression analysis on the data available for 1950-2019 time period. After that, we build a hedonic price index for the canvases of contemporary Russian artists. According to our results, the trend of this index reiterates largely the price behavior for world contemporary art market. However, the results of our study indicate that investments in contemporary Russian art do not outperform investments in instruments of Russian and American capital and real estate markets. We arrived at these results by applying the CAPM model which demonstrated that Russian art as a form of alternative investment is not advisable for the purposes of diversification of investment portfolios. Based on our findings, contemporary Russian art in general can be considered an unattractive instrument for Russian and foreign investors.

We obtain criteria for the L2-dissipativity of finite-difference schemes based on regularizations of 1D barotropic and full gas dynamics systems of equations that are linearized at a constant solution. Bibliography: 8 titles.

We study an explicit in time and symmetric in space finite-difference scheme with a kinetic regularization for the 2D and 3D gas dynamics system of equations linearized at a constant solution (with any velocity). We derive both necessary and sufficient conditions for $L^2$-dissipativity of the Cauchy problem for the scheme by the spectral method. The Courant number is uniformly bounded with respect to the Mach number in them.

Generalized Pauli’s theorem, proved by D. S. Shirokov for two sets of anticommuting elements of a real or complexified Clifford algebra of dimension 2n, is extended to the case, where both sets of elements depend smoothly on points of Euclidean space of dimension r. We prove that in the case of even n there exists a smooth function such that two sets of Clifford algebra elements are connected by a similarity transformation. All cases of connection between two sets are considered in the case of odd n. Using the equation for the spin connection of general form, it is shown that the problem of the local Pauli’s theorem is equivalent to the problem of existence of a solution of some special system of partial differential equations. The special cases n = 2, r ≥ 1 and n ≥ 2, r = 1 with simpler solution of the problem are considered in detail.

It is assumed that a perfect balance between student academic achievement and university quality is beneficial both for students and higher education institutions (HEIs). Matching theory predicts the existence of perfect matching between the two groups in the absence of transaction costs associated with university enrollment. However, in this study we show cases of mismatch situations in Russia under the Unified State Exam (USE) – the standardized student admission mechanism. This research studies the reasons for this phenomenon for minimal transaction costs and the emergence of unequal access to HEIs. Based on data on Moscow high school graduates who entered university, the determinants of the mismatch between the quality of universities and applicant abilities are assessed. It is shown that although in most cases favorable matching results are established, the individual student achievement results themselves are subject to the influence of school and family characteristics. Thus, inequality of access can be formed at stages preceding HEI enrollment.

We consider binary gas mixture flows with viscous compressible components in the absence of chemical reactions. We aggregate the previously derived regularized equations for inhomogeneous mixtures and thus derive new simpler regularized equations for homogeneous ones (i.e., with the common velocity and temperature). The entropy balance equation with the non-negative entropy production is stated for the new equations. They are constructed for numerical simulations of flows.

In this paper, we present all constant solutions of the Yang-Mills equations with SU(2) gauge symmetry for an arbitrary constant non-Abelian current in Euclidean space Rn of arbitrary finite dimension n. Using the invariance of the Yang-Mills equations under the orthogonal transformations of coordinates and gauge invariance, we choose a specific system of coordinates and a specific gauge fixing for each constant current and obtain all constant solutions of the Yang-Mills equations in this system of coordinates with this gauge fixing, and then in the original system of coordinates with the original gauge fixing. We use the singular value decomposition method and the method of two-sheeted covering of orthogonal group by spin group to do this. We prove that the number (0, 1, or 2) of constant solutions of the Yang-Mills equations in terms of the strength of the Yang-Mills field depends on the singular values of the matrix of current. The explicit form of all solutions and the invariant F^2 can always be written using singular values of this matrix. The relevance of the study is explained by the fact that the Yang-Mills equations describe electroweak interactions in the case of the Lie group SU(2). Nonconstant solutions of the Yang-Mills equations can be considered in the form of series of perturbation theory. The results of this paper are new and can be used to solve some problems in particle physics, in particular, to describe physical vacuum and to fully understand a quantum gauge theory.

We consider consecutive aggregation procedures for individual preferences 𝔠 ∈ ℭ_r (A) on a set of alternatives A, |A| ≥ 3: on each step, the participants are subject to intermediate collective decisions on some subsets B of the set A and transform their a priori preferences according to an adaptation function 𝒜. The sequence of intermediate decisions is determined by a lot J, i.e., an increasing (with respect to inclusion) sequence of subsets B of the set of alternatives. An explicit classification is given for the clones of local aggregation functions, each clone consisting of all aggregation functions that dynamically preserve a symmetric set 𝔇 ⊆ ℭ_r (A) with respect to a symmetric set of lots 𝒥. On the basis of this classification, it is shown that a clone ℱ of local aggregation functions that preserves the set ℜ_2(A) of rational preferences with respect to a symmetric set 𝒥 contains nondictatorial aggregation functions if and only if 𝒥 is a set of maximal lots, in which case the clone ℱ is generated by the majority function. On the basis of each local aggregation function f, lot J, and an adaptation function 𝒜, one constructs a nonlocal (in general) aggregation function f_J,A that imitates a consecutive aggregation procesure. If f dynamically preserves a set 𝔇 ⊆ ℭ_r (A) with respect to a set of lots 𝒥, then the aggregation function f_J,A preserves the set 𝔇 for each lot J ∈ 𝒥. If 𝔇 = ℜ_2(A), then the adaptation function can be chosen in such a way that in any profile c ∈ (ℜ_2(A))n, the Condorcet winner (if it exists) would coincide with the maximal element with respect to the preferences f_J,A (c) for each maximal lot J and f that dynamically preserves the set of rational preferences with respect to the set of maximal lots.