SovietRxiv · Open Access in English
Rediscovering the Soviet scientific archive, in English
15152 full-text translations 14873 English PDFs 14653 abstracts
Showing 50 of 15152 papers
This paper studies zero-sum differential games of fixed duration in which one player observes the current state while the minimizing player receives state information only after a fixed lag. A discrete-time approximation is introduced to define information sets, pure, mixed, and behavioral strategie…
This paper studies the one-dimensional reflection of a rarefaction wave from a rigid wall in the products of an instantaneous explosion in a constant gravitational field, for a gas obeying a polytropic equation of state. Starting from the general solution of the gas-dynamic equations for discrete ad…
This paper studies nonlinear interaction in resonant conservative Hamiltonian systems with multiple degrees of freedom, assuming a single resonance relation among distinct linear frequencies. Using a polynomial canonical transformation, the authors reduce the Hamiltonian to a resonant normal form up…
This paper studies a differential game of approach in which two players choose constrained controls entering jointly, rather than separately, in the system dynamics. It formulates the problem in the class of mixed approximating strategies, introduces extremal strategies and a modified notion of posi…
This note interprets Tikhonov regularization for ill-posed statistical optimization problems in control systems from an information-theoretic viewpoint. For a Gaussian signal corrupted by additive Gaussian noise, the authors formulate a regularized mean-square filtering problem and show that the res…
This paper studies repeated two-person zero-sum matrix games in which each pair of pure strategies has both a payoff and a mean duration, and the total encounter time is large but finite or random. It argues that ordinary optimal strategies for the payoff matrix, and generally also those for payoff …
The paper studies one-to-one mappings between affine spaces that send every translate of a fixed bounded set onto a translate of its image, and asks when such mappings must be affine. It introduces shifts preserving a generator and the associated class of quasicylinders, then proves that every conti…
The paper studies growth scales for entire functions of several complex variables through the majorant of the function and the geometry of associated convex or quasiconvex functions. It analyzes Goldberg-type orders and shows how they correspond to scales built from homogeneous logarithmically conve…
The paper studies Fourier expansions of functions in Besov classes with respect to an arbitrary complete orthonormal system of eigenfunctions of a nonnegative self-adjoint extension of the Laplace operator in a star-shaped domain. It establishes estimates for dyadic blocks of Fourier coefficients of…
This paper examines borderline conditions for convergence in the L metric of trigonometric Fourier series and their conjugate series. It constructs a summable periodic function whose integral modulus of continuity, and that of its conjugate function, are both of order 1 divided by log 1 over delta, …
This paper examines gravitational pressure in a conformally flat Friedmann-Lobachevsky space with metric tensor proportional to the Minkowski tensor. It derives expressions for the Christoffel symbols, curvature tensor, and Einstein equations in terms of the conformal factor, then specializes to a d…
The paper develops quotient and decomposition constructions for bicompact spaces designed to separate covering dimension, small inductive dimension, and large inductive dimension. After formulating a general scheme, it constructs families of bicompacta built from ordered compacta, Cantor sets, and m…
This paper studies one-to-one mappings between affine spaces that carry the family of all translates of a bounded set onto the family of translates of its image. Using an iterative construction of associated centrally symmetric sets, it proves that tangent supporting hyperplanes at suitable extreme …
The paper studies a continuous function of three variables, vanishing outside a ball, through three notions of variation defined by the structure, planar sections, and area of its level sets. It proves comparison estimates for partial variations over disjoint balls and a geometric lemma relating loc…
This paper studies separable topological groups containing a Weil-complete almost metrizable normal subgroup, in the sense that the subgroup contains a compact set of countable character. It proves that for such a group G with normal subgroup H, one can choose a subset A of G meeting every coset mod…
This paper analyzes atmospheric wind dynamics on Venus using Doppler measurements from the descent vehicles of the Venera 5 and Venera 6 automatic interplanetary stations. Radial velocity variations during parachute descent are processed after accounting for planetary motion, parachuting velocity, o…
The paper studies the computation of saddle points for twice continuously differentiable functions that are strictly convex in one variable and strictly concave in the other, when both variables are constrained to bounded polyhedra. It characterizes saddle points by the vanishing of distances from t…
This paper derives an analytical attitude control law for a spatial rotational maneuver of a flying vehicle, formulated as a single rotation about a prescribed axis rather than as three successive body-axis rotations. Using Euler equations, inertia transformations, and the principle of extensive con…
Observations of the pulsar CP 0808 at 60 to 110 MHz with the Pushchino DKR-1000 radio telescope are analyzed to characterize its meter-wave radio emission and short-period subpulse behavior. The study finds that pulses consist of one to three subpulses separated on average by 53.6 ms, forming a clas…
This paper examines the resolving power of three-dimensional holograms recorded in volume photosensitive media, where the usual aperture-based treatment of planar holograms is insufficient. Using the kinematic theory of diffraction by three-dimensional periodic structures, the authors derive an inte…
The paper studies when a commutative associative ring without nonzero nilpotents and with torsion-free additive group can be equipped with partial orders compatible with multiplication, especially orders stronger than those of partially ordered rings of functions. It introduces u-cones and phi-cones…
This paper describes the design and testing of a pulsed high-voltage generator using purified water as the dielectric for producing short, intense pulses of fast electrons and hard bremsstrahlung X-rays. The apparatus combines a Marx pulse circuit with a coaxial water-dielectric storage line, which …
The paper refines earlier calculations of the microwave and far-infrared rotational absorption spectrum of the water-vapor dimer, using a linear rigid dimer model with hindered internal rotation about the hydrogen bond. Replacing the harmonic approximation for the torsional barrier by a cosine poten…
The study reports the synthesis and characterization of rare-earth oxytungstate chlorides of composition Ln3WO6Cl3, where Ln is Ce, Pr, or Nd, extending a previously identified group of tungstate chlorides containing chlorine anions. Single crystals were obtained by hydrothermal crystallization in c…
The paper studies the existence of homeomorphic plane mappings between simply connected domains that solve first order elliptic systems whose ellipticity may degenerate. It develops an approximation approach, replacing the degenerate system or the domain by nondegenerate ones and passing to a limit …
The paper studies families of one-to-one mappings between metric spaces equipped with two metrics, motivated by distortion estimates in relative metrics for conformal, quasiconformal, and related mappings. It proves that a uniform two-sided distortion estimate in one metric is equivalent to equicont…
This paper studies whether algorithmically unsolvable mass problems can nevertheless be solved correctly on almost all instances along infinitely many initial segments. For recursively enumerable sets, it proves that for every positive error bound there is a general recursive predicate agreeing with…
This paper examines how solar wind parameters relate to the periods of steady micropulsations in the Earth’s electromagnetic field. Measurements of solar wind ion flux from Venera 2, Venera 4, Venera 5, Venera 6, and IMP 1 are compared with simultaneous telluric current observations from several geo…
The paper studies oscillation of vector-valued solutions of second-order differential equations in finite-dimensional Euclidean and real Hilbert spaces, proposing a coordinate-invariant definition based on zeros of all scalar projections. For equations of the form u''(t) + F(t,u(t))u(t)/||u(t)|| = 0…
The paper studies closed P-sets in bicompact topological spaces, focusing on their role in quasiextremal, or basically disconnected, bicompacts and in the theory of partially ordered vector lattices. It translates earlier results on extended K-sigma spaces into topological terms, showing that for a …
This paper analyzes the spectrum of acoustic turbulence in a compressible potential flow represented as an ensemble of interacting sound waves. Using normal wave variables, resonance considerations, and dimensional Kolmogorov-type arguments, it estimates the nonlinear interaction cone and interactio…
This paper reports measurements of humidity pulsations in the near-surface marine atmosphere during the 1969 Soviet-French expedition in the Mediterranean Sea. Using a low-inertia quartz adsorption humidity sensor connected to digital recording equipment, the study obtained energy spectra under seve…
The paper formulates a mathematical principle intended to express the equivalence of physical objects with respect to a physical law, called phenomenological symmetry. It defines physical structures on two sets through analytic functional relations invariant under permutations of selected elements, …
The paper studies mixed boundary value problems for partial differential equations in which part of the boundary carries nonstationary conditions, reducing them to Cauchy problems for evolution equations in orthogonal sums of Hilbert spaces. It constructs an operator generated by an elliptic boundar…
The paper reports a single-crystal X-ray determination of the crystal structure of sodium zirconium oxyorthosilicate, Na2ZrSiO5, a compound of interest in alkali zirconia silica systems used for heat-resistant materials and adsorbents. Using Patterson and electron-density syntheses followed by least…
This paper examines the origin of longitudinal waves observed in 4 to 6 second microseisms recorded in a quiet intracontinental region. Using wave-number decomposition of microseismic fields from a station group near Ust-Kamenogorsk, the study estimates apparent velocities, azimuths, and source loca…
The paper studies a Tricomi boundary value problem for a class of mixed type equations with parameter \(\lambda\), aiming to obtain estimates without assuming smallness of the coefficient or of the transition interval. By introducing an exponential substitution based on a Riccati equation and applyi…
The paper studies the partially ordered set of equivalence classes of H-closed extensions of a Hausdorff space, ordered by admissible continuous maps. It proves that every nonempty family of such extensions has a supremum, using products of representative extensions, the diagonal copy of the origina…
The paper determines the crystal structure of the mineral calciborite and evaluates its chemical formula in light of earlier analytical and synthetic-polymorph data. Using Weissenberg X-ray diffraction intensities, Patterson methods, electron-density syntheses, and least-squares refinement in the or…
The paper studies an intrinsic characterization of relatively open convex subsets of real vector spaces through abstract axial structures, formalizing order-theoretic notions of lines, segments, convexity, dimension, and parallelism. It introduces a Euclidean condition for generalized vector spaces …
The paper proposes a regularization of singular operator expressions in quantum field theory, applied to the Hamiltonian of the scalar fourth-power interaction. It constructs a modified Fock-type Hilbert space using a positive symmetric kernel and defines corresponding analogues of annihilation and …
This note studies shift families on the real line for which the optimal homogeneous estimator is essentially independent of the chosen symmetric loss or quality criterion. It defines strongly symmetric densities through a zero set condition and shows that, under regularity assumptions, such laws are…
This paper formulates and solves an integral geometry problem for a pair of oriented real Grassmann manifolds, the spaces of l-dimensional and k-dimensional subspaces of Euclidean n-space, under the assumptions l < k, l + k ≤ n, and even k minus l. It defines a transform from homogeneous smooth func…
The paper examines whether impurity ions of higher charge in a plasma carrying a strong electric current can attain directed energies sufficient for nuclear synthesis with the principal ions. Using Gurevich’s two stationary states of impurity ion motion under Coulomb conductivity, it estimates react…
This paper interprets an observed break near 290 degrees Celsius in the thermal expansion coefficients of artificial fluorophlogopite along the a and b axes, with no corresponding anomaly along c, as evidence for a second-order phase transition confined to the basal plane. Using geometric relations …
This paper studies locally bicompact topological groups through the topology on classes of conjugate closed subgroups, identified with quotient spaces by normalizers. It proves that if conjugacy classes of bicompact subgroups topologically generated by one element are bicompact, then the bicompact e…
This paper studies uniqueness in mixed inverse problems of potential theory, especially the determination of both the shape of a body and its density from exterior volume potentials or simple-layer potentials. Using the method of generalized moments, it proves uniqueness theorems for classes of cont…
This paper treats the direct problem of unsteady and steady ideal-gas flow in Laval nozzles of prescribed geometry, including subsonic, transonic, and supersonic regions. The authors formulate the gas-dynamic equations in transformed coordinates and describe a finite-difference marching algorithm wi…
