RussiaRxiv · Open Access in English
Translated research papers from Russian journals and repositories
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Showing 50 of 15134 papers
Generated abstract This paper develops an averaged continuum-mechanical formulation for anisotropic turbulent flows in which Reynolds stresses need not be symmetric. Starting from asymmetric continuum mechanics, including independent conservation of angular momentum and intrinsic angular momentum, it derives macroscop…
Generated abstract The paper studies continuation and branching of periodic solutions for quasilinear differential-difference equations with a small parameter. Using an auxiliary equation and analytic expansions, it derives a finite-dimensional branching equation whose small solutions are in one-to-one correspondence …
Generated abstract This paper proposes a method for estimating the small supersaturations that arise during formation of the droplet liquid phase in clouds, a quantity difficult to measure directly but important for droplet growth. Using a model of hydrated condensation nuclei, the authors derive and test simplified r…
Generated abstract The paper considers the Euler-Poisson equations for a heavy rigid body with a fixed point when the center of gravity lies on the first principal axis and the gyrostatic moment is perpendicular to the third axis. Under a specified algebraic relation among the moments of inertia and a two-parameter re…
Generated abstract The paper studies convergence and asymptotic rates for iterative processes used to solve finite-dimensional linear systems, allowing generally nonlinear transition operators. It introduces subordinate functionals as Lyapunov-type tools and proves a convergence criterion based on monotonic decrease, …
Generated abstract This paper studies the existence of invariant torus-like surfaces near an equilibrium of analytic systems of differential equations whose coefficients are periodic in time. Extending earlier results for special second-order systems, it applies Kolmogorov’s Newton method under nonresonance conditions…
Generated abstract This paper studies nonlinear equations of the form x = SF(x) and x = BF(x) in Banach spaces, where F is either a potential operator or a monotone operator and the associated linear operator may be bounded or unbounded. It formulates structural conditions linking a Banach space with an auxiliary Hilb…
Generated abstract This paper studies the growth of meromorphic functions of finite lower order through the quantity measuring minimal deviation from a value, defined using the maximum proximity relative to the Nevanlinna characteristic. It establishes upper bounds for this deviation in terms of the lower order, prove…
Generated abstract This paper proposes a general iterative approach to minimizing nonlinear functionals on closed convex bounded subsets of reflexive Banach spaces, using convex Taylor-type approximations and an adaptive step-size rule. The main convergence theorem establishes monotonic decrease and, for convex functi…
Generated abstract The paper gives an axiomatic characterization of categories of correspondences associated with semi-abelian categories, beginning with the more general case of beta-categories, which need not have direct sums or products. It defines beta-categories through kernel, cokernel, exactness, and intersecti…
Generated abstract This paper studies limiting distribution functions for real multiplicative arithmetic functions through Zolotarev’s characteristic transform and summation theorems for multiplicative functions. It gives necessary and sufficient convergence criteria for the empirical distributions of values of a mult…
Generated abstract The paper develops a direct normal-wave expansion for radio-wave fields in a spherically layered isotropic dissipative medium with complex dielectric permittivity. Using spectral results for non-self-adjoint differential operators, the radial normal-wave operator is transformed to a Schrödinger-type…
Generated abstract This paper studies complexity bounds for normal algorithms and for deciding enumerable sets when computation time is restricted. It first proves a coding theorem showing that algorithms constructively generated from words over one alphabet can be represented over a two-letter extension of another al…
Generated abstract This paper addresses the computation of the characteristic criterion for the periodic limiting regime of motion of a machine unit, a quantity needed in dynamic machine calculations but generally unavailable in closed form. Under standard continuity, periodicity, and monotonicity assumptions on the r…
Generated abstract This paper studies global Cauchy problems for nonlinear first order equations, including multidimensional scalar conservation laws with bounded measurable initial data and a one dimensional Hamilton-Jacobi type equation with Lipschitz initial data. It introduces entropy-type definitions of generaliz…
Generated abstract The paper proves a duality theorem for the K-groups of homology and a slightly modified version of K-cohomology for subsets of a closed oriented homological manifold. For a decomposition of such a manifold into complementary sets A and B, under K-acyclicity assumptions in two adjacent dimensions and…
Generated abstract The paper gives a criterion for a T1 space to be homeomorphic to a metric space of covering dimension at most n: it must have a regular base whose element boundaries form a family of multiplicity at most n. Using properties of regular bases, locally finite refinements, and standard results from dime…
Generated abstract The paper studies finite-dimensional subspaces of Banach coordinate spaces for which fixedness, or asymptotic fixedness, of contractive linear operators on the subspace implies the corresponding property on the whole space. It formulates these questions in terms of saturated and completely saturated…
Generated abstract This paper studies an inverse problem in magnetic prospecting for a two-dimensional star-shaped body whose magnetization is not known in advance. Using the method of artificial magnetization by a steady current in an external ungrounded cable, the direct problem is formulated through a simple-layer …
Generated abstract This paper examines a proposed acceleration and extraction regime for improving the energy uniformity of beams from an isochronous cyclotron without requiring extremely tight stabilization of the accelerating voltage. The authors analyze extraction near the boundary of radial stability, where the ma…
Generated abstract The paper studies trace and extension problems for functions on Euclidean space whose Hilbert norms are defined by generalized Fourier type operators depending on a function of position and frequency. By reducing a smooth hypersurface to a coordinate hyperplane, it formulates conditions under which …
Generated abstract The paper studies nondeterministic numerical methods for the first Dirichlet problem for the Poisson equation in the unit square, with right-hand sides bounded in a Sobolev class. It constructs a randomized approximation based on values at order N squared points, using local orthonormal polynomial e…
Generated abstract The paper presents iterative methods for sectoral planning problems formulated as integer linear programs with binary variables and assignment-type restrictions. It first describes a primal-dual iterative procedure for the corresponding continuous linear programming relaxation, using adaptive price …
Generated abstract This paper examines representations of stationary electromagnetic fields in layered media as expansions in normal waves, formulated through differential operators associated with directions along and across the layers. It relates contour-integral methods based on residues to direct expansions in eig…
Generated abstract The paper studies the long-time behavior of solutions to the Schrödinger equation for a particle initially in a bound state behind an infinite potential barrier that is then replaced by a finite, sufficiently high barrier. Under regularity and compact-support assumptions on the potential, the author…
Generated abstract This note studies intrinsic properties of strongly closed mappings between Hausdorff spaces, a class previously shown not to lower dimension. It establishes basic permanence results, including behavior under restrictions, inverse spectra with perfect projections, and directed systems, leading to the…
Generated abstract This paper argues that long-term measurements of oceanic physical fields on fixed polygon arrays represent a new stage in ocean research, shifting attention from presumed stability toward statistically interpreted variability and macroturbulence. It reviews earlier Caspian, Black Sea, and Atlantic p…
Generated abstract This paper analyzes the effect of Coriolis force on long unsteady axisymmetric waves in an ideal incompressible fluid in a uniformly rotating basin. A point source with arbitrary time-dependent discharge is introduced at the origin, and the linear long-wave equations are solved by Laplace-Carson tra…
Generated abstract This note constructs a semiphenomenological Green’s function for the optical electron in a complex atom within the quantum defect approximation. The authors solve the radial Coulomb Green’s function problem with phase shifts representing deviations from a pure Coulomb core field, then analytically c…
Generated abstract The paper studies an extension of Zermelo-Fraenkel set theory obtained by adding a formal truth predicate for formulas under valuations, together with axioms governing this predicate. Within this system, the authors construct absolute natural transitive models of ZF and define ordinals that serve as…
Generated abstract The paper classifies Lie subgroups of the Lorentz group that have positive dimension and a finite group of connected components. Using the spinor representation of the Lorentz group and the known classification of its real Lie subalgebras, it determines the normalizers of the connected subgroups and…
Generated abstract The paper examines whether crystalline ordering can occur in one-dimensional quantum systems of identical Bose or Fermi particles at nonzero temperature. Using Bogolyubov’s inequality for temperature Green’s functions, the authors derive a bound on density correlation functions near a reciprocal lat…
Generated abstract The paper proposes a numerical algorithm for scalar diffraction by a bounded body when the incident wavelength is comparable with the object size and the exterior medium may have coordinate-dependent properties. The exterior boundary-value problem with impedance conditions is reduced by introducing …
Generated abstract This paper formulates and solves a finite control problem for a distributed linear system governed by a one-dimensional wave equation, seeking a boundary control that brings the system to rest in a prescribed finite time. The solution applies a Fourier transform in time, the Paley-Wiener theorem, an…
Generated abstract The paper solves the Milne boundary problem for the one-dimensional Bhatnagar, Gross, and Krook kinetic equation with an absorbing wall, motivated by dilute gas mixtures, low-temperature plasma, chemical kinetics, and neutron transport. Using a one-sided Fourier transform, the boundary condition is …
Generated abstract The paper examines the formulation of equations for a rolling wheel with an elastic tire undergoing oscillations, focusing on the relation between tire deformation and ground reaction. Using transverse oscillations of the wheel rim as an example, it models the tire as a weightless elastic beam on an…
Generated abstract The paper extends Berman’s study of functors on locally convex spaces by associating to each reflexive K-space with a suitable topologizing system a functor defined through spaces of measurable vector-valued functions. It proves comparison and representation results for these spaces, including condi…
Generated abstract This note derives a central limit theorem for certain narrow-sense stationary random processes by reducing the problem to the known central limit theorem for stationary sequences of martingale differences. For an ergodic measure-preserving transformation and an associated decreasing filtration, it g…
Generated abstract This paper studies averaging methods for nonlinear integro-differential equations with a small parameter, motivated in part by equations arising in the dynamics of imperfectly elastic bodies. It formulates and proves averaging theorems for systems with slow variables on finite intervals of order inv…
Generated abstract This paper examines the conditions governing isomorphous substitution of atoms in solid solutions formed by intermetallic compounds. It argues that, beyond similarities of chemical nature, crystal structure, and atomic size, a more fundamental criterion is the mutual chemical indifference of atoms o…
Generated abstract The paper develops a general condition for complete regeneration in a regenerative optocoupler using a photoresistor, extending earlier treatments that assumed more restricted device characteristics and input configurations. Starting from a system of equations for an optocoupler with electrical and …
Generated abstract This paper generalizes a previously established symmetry principle for shallow geometrically nonlinear shells to a more exact nonlinear shell theory and to shallow equilibrium forms of nonshallow shells. Using compatibility and equilibrium equations in orthogonal curvilinear coordinates, the author …
Generated abstract The paper studies a linear conjugation problem for a holomorphic vector with values in a Banach space of infinite sequences on a Lyapunov contour, with boundary relation determined by an infinite functional matrix. Under bounded invertibility and compactness assumptions on the matrix coefficient, it…
Generated abstract A method is developed for spatial doubly periodic boundary value problems in elasticity for an infinite body perforated by parallel cylindrical cavities whose circular cross sections form an oblique lattice. Using Galerkin’s general solution of Lamé equations and addition theorems for modified Besse…
Generated abstract The paper studies the Cauchy problem for the linearized Navier Stokes equations of an incompressible viscous fluid subject to uniform rotation. Using Fourier transformation, Bochner’s formula, and Sonine formulas for cylindrical functions, it constructs explicit fundamental kernels for the velocity …
Generated abstract This paper examines the transition from laminar to turbulent motion through measurements of the frequency spectra of longitudinal velocity fluctuations in air flowing through a circular tube. Using hot-wire anemometry and low-frequency spectral analysis at several radial positions, the authors compa…
Generated abstract The paper examines transformations of the Schwarzschild metric to a synchronous reference system and argues that the usual choice of the arbitrary radial function removes the horizon singularity but gives an unsatisfactory flat-space limit. It proposes choosing the function so that, when the gravita…
Generated abstract This note relates the Schauder fixed point principle to stability questions for periodic solutions of nonlinear differential equations. It proves two abstract results for completely continuous operators in Banach spaces: a characterization of asymptotic stability in terms of isolation and index of a…
Generated abstract The paper studies finitely convergent iterative algorithms for solving countable systems of inequalities that arise in the synthesis of adaptive control systems, where the inequalities are revealed sequentially and may contain unknown quantities. It develops several correction algorithms for quadrat…
Generated abstract This paper examines the high temperature dissociation of oxygen molecules in collisions with O2 and O, addressing the inadequacy of extrapolating lower temperature rate constants to regimes above about 10,000 K. Shock tube experiments in a 10 percent O2 and 90 percent Ar mixture used ultraviolet abs…
