SovietRxiv · Open Access in English
Rediscovering the Soviet scientific archive, in English
25357 full-text translations 14926 English PDFs 22539 abstracts
Showing 50 of 25357 papers
This paper investigates ionization instability in a weakly ionized argon and cesium plasma subjected to crossed electric and magnetic fields, where anisotropic conductivity can amplify density and conductivity fluctuations. The authors combine linear stability estimates with pulsed discharge experim…
The paper studies gaps between neighboring prime ideals in an algebraic number field through analytic properties of the associated Dedekind zeta function. Using Vinogradov’s method for estimating trigonometric sums, together with derivative estimates and a reduction to exponential sums over lattice …
The paper extends Moser’s method for Harnack inequalities to generalized solutions of a class of second order quasilinear parabolic equations. After establishing an embedding estimate for functions in parabolic Sobolev spaces, it proves a local Harnack inequality for nonnegative generalized solution…
This paper studies plane self-similar nonisentropic flows of a polytropic gas with variable entropy, using a hodograph formulation in which density and entropy are treated as functions of the velocity components. It derives a closed system of partial differential equations for these functions and sh…
The paper proposes a general iterative method for extremal problems in Hilbert space with quasiconvex, possibly nonsmooth objectives and constraints. Instead of using gradients, the method moves along arbitrary supporting vectors to either the objective level set, when the current point is feasible,…
The paper studies irreducible and indecomposable Harish-Chandra modules over the Lie algebra of the proper Lorentz group, defined by their finite-multiplicity decomposition with respect to the maximal compact rotation subalgebra. It reduces the classification to algebraic categories determined by th…
This paper studies extremal sequences of regularly monotone polynomials on the interval [0,1] with periodically prescribed type numbers. It characterizes the derivatives of extremal polynomials, proves their least deviation property under endpoint vanishing conditions, and shows that the resulting s…
This paper examines how cooperative molecular motion in liquids affects the intermolecular, translational contribution to nuclear magnetic relaxation times. It replaces the usual independent relative diffusion model with a Smoluchowski equation containing a hydrodynamic interaction tensor, then eval…
This review discusses A. V. Bitsadze’s monograph on boundary value problems for uniformly elliptic linear second-order partial differential equations and systems. It summarizes the book’s treatment of Dirichlet and oblique derivative problems, qualitative properties of solutions, fundamental solutio…
This paper generalizes Kolmogorov’s theorem on the density of points of local topologicity for countable-to-one open mappings by introducing the broader class of preopen mappings. It proves that a locally countable-to-one preopen mapping from a locally bicompact Hausdorff space has a dense set of po…
This paper studies partial sufficiency for repeated samples from a distribution with a shift parameter, with emphasis on polynomial estimators of functions of the parameter. It replaces ordinary partial sufficiency by a Hilbert space formulation for polynomials of bounded degree, defining sufficienc…
The paper studies individual asymptotic estimates for the number of integer solutions to Diophantine inequalities of the form measuring the distance of αq + β to the nearest integer against a decreasing function χ(q). It proves that when α satisfies a finite exceptional approximation condition, the …
The paper constructs a Green function for a two-sheeted Riemann space whose branch line is an ellipse, extending earlier potential-theoretic treatments of spaces with slits. Using coordinates adapted to an elliptic contour, it gives explicit integral formulas for the Dirichlet and Neumann problems i…
This paper studies Green matrices for homogeneous boundary value problems associated with linear Petrovsky parabolic systems satisfying the algebraic Lopatinskii condition. It proves that the solution operator is an integral operator and derives sharp pointwise and Hölder type estimates, up to the b…
This paper studies minimax algorithms for locating the unique root of a continuous function on an interval when the function is known only through approximate evaluations with prescribed error bounds and slope constrained between two positive constants. Using dynamic programming ideas, it characteri…
This paper examines the classification of electronically excited states in uranyl compounds from electronic vibrational absorption and emission spectra. Arguing against a five state scheme that assigns ultraviolet absorption bands to the uranyl ion, the authors interpret experimental spectral eviden…
This note develops a constructive-mathematical definition of generalized functions, modeled on the Mikusinski, Sikorski, and Korevaar approach. It first formalizes almost uniformly continuous functions, primitives, polynomial germs, and fundamental sequences of constructive function codes, then defi…
The paper examines proposed routes to high critical temperature superconductivity based on an electronic, excitonic attraction mechanism rather than phonon exchange. It argues that spatially separating a thin conducting region from a highly polarizable nonmetallic medium could enhance this mechanism…
This paper studies optimal impulsive transfers between close, near-circular, non-coplanar orbits using a linearized orbital theory valid in a neighborhood of a reference circular orbit. The transfer is formulated as a multi-impulse optimization problem minimizing total characteristic velocity, with …
The article proves the following theorems: 1) If $A(t)$ is recurrent, then the system $\dot{x}=A(t)x$ can be reduced to the triangular form $\dot{u}=P(t)u$ with a recurrent matrix $P(t)$ by a Perron transformation $x=U(t)u$ with a recurrent matrix $U(t)$. 2) If $A(t)$ is almost periodic, then for th…
The paper studies multiplicative representations of the characteristic functions of contraction operators in a separable Hilbert space whose spectrum lies on the unit circle, with compact defect operator and a chain separating the spectrum. Building on work of Gohberg and Krein, it proves their conj…
This paper studies open continuous mappings in completely regular spaces, with emphasis on locally complete spaces and sigma-discrete or countably multiple fibers. It generalizes results of Aleksandrov and Kolmogorov by proving density of points of local topologicity for open locally sigma-discrete …
The paper studies restrictions on the induction schema in Kleene-style formal arithmetic, especially systems in which induction formulas contain at most a fixed number of quantifiers. Using Novikov’s method of regular classes, it shows that for every such bound there are formulas provable in full ar…
This paper studies the boundedness in Lp spaces of singular Cauchy-type integral operators taken over rectifiable Jordan curves whose tangent angle has bounded variation. It first establishes boundedness, and under continuity of the tangent angle compactness, for the real operator with kernel given …
The main results of the authors' previous note are generalized to a general linear second-order parabolic equation with a sign-definite lower-order coefficient $c(x,t)$ under very general boundary conditions. The presentation is primarily conducted for the case of a one-dimensional problem with cont…
This paper studies angular boundary values of quasiconformal mappings of a ball in Euclidean space. Using moduli of curve families, generalized curves, and capacity estimates, it proves that the exceptional set of boundary points at which angular boundary values fail has outer capacity zero: logarit…
Dragalin studies how parts of the theory of countable transfinite numbers can be transferred to constructive mathematics, with particular attention to defining algorithms by transfinite recursion. The paper introduces constructive transfinite systems equipped with a constructive order and transfinit…
This paper derives thermodynamic compatibility relations for a strong discontinuity, or velocity-discontinuity wave, propagating in an elastic medium under finite deformation, using Eulerian variables and the Almansi strain tensor. Conservation of mass, momentum, and energy are combined with the sec…
This paper studies a differential game of pursuit for two linear controlled motions with bounded controls, where the pursuer seeks coincidence of specified coordinates in minimal worst case time. It relates the feedback synthesis problem to programmed minimax problems and formulates an extremal aimi…
The paper extends the averaging method to ordinary differential systems not solved explicitly with respect to the derivative, focusing first on equations of the form x dot equals epsilon times a function depending on time, the state, and the derivative. Under boundedness, Lipschitz, and uniform mean…
The paper studies best approximation by algebraic polynomials in the spaces \(L_q(-1,1)\), \(1 \le q \le \infty\), for functions with real singularities of the form \((x-a)^r |x-a|^\alpha \ln^m |x-a|\). Using a general limit theorem of S. N. Bernstein, it proves a generalized Bernstein-type inequali…
This note addresses lattice coverings of Euclidean space by equal balls, focusing on when the classical lattice associated with Voronoi’s principal form of the first type ceases to be optimal among lattice coverings. Using a modified lemma of Davenport and an analysis of orthogonal projections of Kr…
This paper develops electrodynamic equations for two-band superconductors, including both pure systems and systems with impurities, using temperature Green functions derived from a two-band Hamiltonian. By expanding the resulting integral equations for small order parameters, it obtains Ginzburg-Lan…
The paper studies systems of linear inequalities over an arbitrary ordered field and extends earlier results on polyhedrally closed systems beyond the real case. It defines polyhedral closedness via dual cones, develops the notion of hulls or convolutions with respect to subspaces, and gives consist…
This paper studies groups that are factorizable with respect to the system of all noninvariant subgroups, meaning that each such subgroup has a complement in the group. Building on earlier work on completely factorizable and primitively factorizable groups, it formulates an exhaustive classification…
This paper gives algebraic interpretations of Steiner triple and quadruple systems in terms of TS-quasigroups, TS-loops, and S-algebras with a ternary operation satisfying specified identities. It establishes one-to-one correspondences between Steiner triple systems, TS-quasigroups, and TS-loops, an…
This paper experimentally examines the range over which Bouguer’s law can describe the attenuation of narrow collimated light beams in scattering media, a question important for optical quantum generator applications in communication and transmission systems. Using gas and ruby lasers, collimated th…
The paper examines conditions under which a continuous supersonic region behind a detached shock wave breaks down in symmetric flow of an ideal gas past a convex profile. Using characteristic compatibility relations and assumptions on uniqueness, entropy monotonicity, and continuity in the minimal d…
This note studies contractible curves on nonsingular complex surfaces that preserve the canonical class, focusing on the curves whose contractions give rational double singularities. Using obstruction calculations for extending isomorphisms of infinitesimal neighborhoods, it proves that neighborhood…
The problem of approximate motion along a given trajectory is considered for the system $$\frac{dy}{dt}=Y(y,t,v)+g(t),$$ where $y$ is an $n$-dimensional vector of phase coordinates, and $v$ is an $r$-dimensional vector of control forces; $Y(y,t,v)$ is a given vector function characterizing the dynam…
This paper proposes a particle-based model for nondissipative continuous media in which mass, energy, and momentum components are treated symmetrically as conserved quantities satisfying continuity equations. The author formulates trajectories for finite particles representing each conserved quantit…
