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 biographical survey marks the fiftieth anniversary of A. V. Bitsadze and reviews his scientific and pedagogical work in partial differential equations. It outlines his career from Tbilisi to the Steklov Institute and the Siberian Branch of the Academy of Sciences, then summarizes major contribu…
The paper studies transformations of variational optimal control problems for differential equations with compact control sets, focusing on when the original problem is well posed in terms of continuous dependence of endpoint control classes. It proves that, under this well-posedness condition, the …
This paper studies symmetric representations of rings with involution by bounded operators on spaces with indefinite metric of type Pi_n, extending invariant subspace results of Pontryagin and Naimark. Using decomposition lemmas for adjoint-closed operator families, a finite-dimensional perturbation…
This paper examines a gallium arsenide semiconductor quantum generator using a plane Fabry Perot resonator, motivated by limitations on output power in conventional resonator geometries caused by absorption, scattering, thermal effects, and electron penetration constraints. An n-type GaAs plane-para…
The paper introduces n-perfect mappings as a generalization of perfect mappings, using Čech growths of finite order and the classes K_n to describe compactness type properties of point inverses and behavior at infinity. It states a series of theorems relating n-perfectness, closedness of successive …
The paper studies best uniform approximation of continuous and differentiable functions on an interval by algebraic polynomials, comparing it with known results for trigonometric approximation of periodic classes with prescribed moduli of continuity. It establishes asymptotically sharp lower and upp…
This paper examines lunar solar fortnightly and lunar monthly long period tides in the seas of the Soviet Arctic, where high latitude conditions make such oscillations especially significant. More than 100 annual cycles of sea level observations from 22 Arctic stations are analyzed by harmonic metho…
This paper addresses the forensic problem of distinguishing similar handwritings, especially genuine and forged signatures, by means of an electronic computer treated as a learning recognition machine. It formalizes handwriting samples as points in a Euclidean handwriting space obtained by metrizing…
This paper examines vibrocreep in polymer materials, focusing on whether the acceleration of creep under small superposed vibrations can be explained by vibrational heating rather than by a separate mechanical effect. Experiments on caprolite specimens under static load and a small dynamic load are …
This note studies extremal problems for quasiconformal homeomorphisms between closed Riemann surfaces of genus greater than one, in a fixed homotopy class and with bounded maximal dilatation, maximizing a real functional depending on the images of finitely many points. Using Teichmüller theory, vari…
This note studies time-optimal control problems in which the admissible control set depends on the phase coordinates and is described by inequality constraints that may change across lower-dimensional subsets of the phase space. Extending sufficiency results related to Boltyanskii’s work on the maxi…
The paper develops a method for treating variational and optimal control problems with inequality constraints on controls or coordinates by replacing the constrained quantities with trigonometric transformations, especially sine functions. This converts the nonclassical problem with one-sided variat…
The paper studies Green’s functions for a Bardeen-type model Hamiltonian with a factorizing interaction kernel at nonzero temperature, extending earlier zero-temperature results. Using an approximating quadratic Hamiltonian, the argument estimates derivatives of the free-energy difference with respe…
The paper studies the asymptotic behavior of the resolvent of an integral equation on expanding star-shaped domains, for kernels depending only on the difference of variables and satisfying Fourier-transform positivity and integrability assumptions. Using an orthogonal system adapted to the weighted…
This paper studies the restriction to the real unimodular subgroup of a complementary series representation of the complex unimodular group of order two, where the restricted representation is reducible. The analysis first treats the subrepresentation on functions supported in the upper half-plane, …
This paper reports a neutron-diffraction investigation of manganese telluride at temperatures above and below its antiferromagnetic transformation, motivated by the compound’s combined semiconducting and magnetic properties. Diffraction patterns measured between 120 and 373 K confirm the NiAs-type c…
This paper proves a theorem on simultaneous approximation of a function and its derivatives by algebraic polynomials on a finite interval. For functions with a continuous r-th derivative on [-1,1], it constructs an explicit polynomial of degree at most n whose derivatives up to order r approximate t…
This study addresses the limited technical use of crystalline silver chloride, despite its broad optical transparency and favorable plasticity, due to low hardness and pronounced sensitivity to visible and ultraviolet radiation. Silver chloride crystals were grown by a modified Stockbarger method wi…
The paper proves two results in general topology concerning continuous decompositions and finite-to-one mappings. First, for a regular space with a symmetrix and a continuous closed map onto a T1 space, it shows that the range splits into a sigma-discrete exceptional part and a part over which all i…
The paper analyzes free vibration frequencies in branched chains of diatomic molecules, distinguishing two structural types and separating small oscillations into in-plane and out-of-plane components. It formulates equations of motion for the displacement components, reduces the frequency problem to…
The paper studies quasianalytic continuation of analytic functions defined on two nonintersecting Jordan domains whose boundaries share an arc. It introduces classes of functions characterized by rational approximation with poles confined to derivable singular sets and by geometric rates of converge…
The paper studies the Milne problem for radiative transfer in a semi-infinite plane layer with an arbitrary scattering phase function, allowing azimuthally inhomogeneous solutions. It formulates the problem as an operator equation in weighted Bochner spaces, establishes mapping and convergence prope…
This paper studies non-oscillation for an nth order linear difference equation on a finite mesh and related nonlinear difference boundary value problems. Using estimates for mesh functions with prescribed sign changes, based on convexity and extreme point arguments, it derives criteria for non-oscil…
This note proves an exhaustion theorem for the irreducible unitary representations of the group of second order matrices over a disconnected locally compact nondiscrete field, focusing on the determinant one subgroup. It recalls the continuous, supplementary, special, discrete, and one dimensional d…
The paper develops a Lyapunov based method for studying stability of differential systems with aftereffect, where derivatives depend on delayed state functions. By reversing time, the delayed system is associated with a system with advance, allowing the derivative of a positive definite function to …
This note studies unique continuation properties for second order linear parabolic equations when the coefficients may depend on both time and one spatial variable. Extending a result of Ito and Yamabe for time-independent coefficients, it proves that a solution in a bounded space-time domain with z…
This paper studies the multiplicity of stationary solutions for boundary-value problems arising in mathematical models of catalytic chemical processes. It reduces several parabolic and reactor models to nonlinear ordinary differential or integral equations, derives functional equations for determini…
This note studies the distribution of solutions to the Hardy, Littlewood type equation p plus xi squared plus eta squared equals n, where p is prime and the integer point xi, eta is restricted to a growing planar domain inside the circle of radius square root n. Extending earlier asymptotic formulas…
This paper studies a minimax problem for cubature formulas by estimating the formula error as the norm of a continuous linear functional on weighted Hilbert spaces of generalized functions. Using Fourier transforms, the author derives extremal functions for the error functional in spaces defined by …
This note studies the block length required to achieve a prescribed absolute redundancy in optimal decodable binary coding of independent source letters with given probabilities. It relates the asymptotic behavior of the redundancy A(n) to arithmetic properties of the logarithmic probability ratios,…
This paper reports a neutron diffraction study of spin ordering in hexagonal W type ferrites of composition BaCo x Fe2-x Fe16O27, using polycrystalline and single crystal samples with varying cobalt content over 77 to 770 K. The authors compare measured magnetic reflection intensities with calculati…
Measurements from the Luna-10 artificial lunar satellite are used to examine the magnetic field in the vicinity of the Moon during April and early May 1966. Three-component ferrosonde magnetometer data from communication sessions show a regular field with total intensity about 23 to 40 gamma, with r…
This paper investigates whether the distinctive forest blowdown pattern produced by the 1908 Tunguska event can be explained by an elevated airburst associated with a supersonic meteoric body. Using field measurements of fallen tree azimuths and scale experiments with an inclined detonating cord and…
The paper proposes a class of stable superdense quasiparticles, termed planckeons, constructed from Planck-scale combinations of gravitational, quantum, and relativistic constants. It argues that such objects would have a mass of about 10^-5 g, a size equal to both their gravitational radius and int…
This paper investigates the elliptical polarization of optical radiation from the Crab Nebula, motivated by synchrotron emission from ultrarelativistic electrons in a magnetic field. The authors develop and apply a polarimetric method using observations with and without a near quarter-wave phase pla…
This paper analyzes gradient instability in semiconductors carrying current in nonuniform electric and magnetic fields, extending earlier treatments based mainly on carrier concentration gradients. Using linearized continuity, transport, and Poisson equations in a WKB approximation, the authors deri…
This paper studies stationary motions and stability of holonomic mechanical systems with cyclic coordinates using the Routh reduction and related results of Routh, Poincaré, Kelvin, Lyapunov, and Chetaev. It formulates stability and instability criteria in terms of the reduced potential function, th…
The paper examines the observed nonreciprocal attenuation of very low frequency radio waves propagating in opposite directions around the Earth during daytime, attributing it to ionospheric anisotropy in the geomagnetic field. It extends waveguide theory by incorporating the horizontal as well as ve…
The paper studies continuous isomorphisms of spaces of analytic functions in a disk and of entire functions that commute with a power of the differentiation operator. It shows by counterexample that earlier descriptions by Delsarte, Lions, and Viner do not give the full group for powers of order at …
This paper examines flute, or interchange, instability in an ideally conducting plasma confined in toroidal discharges of Tokamak type, where the longitudinal magnetic field is much stronger than the azimuthal field and the usual straight-column Suydam criterion is not directly applicable. The autho…
This paper analyzes the upper critical load for loss of stability of a rigidly supported strictly convex shell subjected to a concentrated normal force through a rigid reinforcing element. Using the stationarity condition for the functional equal to deformation energy minus external work, it charact…
