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 note derives Schauder-type estimates for the first boundary value problem for parabolic equations of order 2p, with p greater than 1, in bounded domains with suitably regular lateral boundary. The argument replaces techniques specific to second-order equations by an improved estimate for the de…
This study examines the formation of dense modifications of germanium and silicon under the combined action of high pressure and shear stress at room temperature. Using a calibrated high-pressure apparatus, the authors compressed germanium to 120 kbar and silicon to 200 kbar while applying shear str…
The paper studies locally finite groups containing a maximal complete abelian 2-subgroup whose normalizer is 2-infinitely isolated. It proves a structural alternative: under these hypotheses, either an almost regular involution is finitely approximable, the group is of type PGL(2,K) over a field of …
This paper studies the Cauchy problem for linear differential operators in a Banach space using weak approximation, without assuming in advance that the original problem is well posed. It introduces an auxiliary factorized problem corresponding to a decomposition of the operator into fractional step…
This paper studies the Dirichlet problem for the elliptic system of A. V. Bitsadze, focusing on how the Noether property fails in simply connected noncircular domains. Reducing the system to the complex equation with general solution expressed through holomorphic functions in the Smirnov class, the …
The paper establishes a priori estimates for one-dimensional parabolic equations whose coefficients may be merely measurable and may depend on the solution and its spatial derivative. Using an auxiliary spatial variable and a boundary smallness lemma for a related higher-dimensional quasilinear equa…
The paper studies invariant maximal positive and negative subspaces for bounded linear operators in Hilbert spaces with an indefinite metric. It proves property P for certain J-unitary operators with compact off-diagonal part, establishes existence and extension results for invariant maximal nonnega…
The paper studies infinitesimal bendings of convex surfaces subject to nonsingular sleeve, or collar, boundary constraints, with emphasis on how nonrigid constraints are distributed among all such constraints. Using reductions to elliptic boundary value problems and compact operator arguments, it pr…
The paper examines conditions under which the standard classical formula for photocurrent shot noise may fail in a quantum system. Using perturbation theory for an optically thin transparent semiconductor illuminated by monochromatic radiation near the red edge of the absorption band, it derives the…
The paper reports an X-ray crystallographic determination of the synthetic sodium zincosilicate phase Na2ZnSiO4, obtained hydrothermally in a strongly alkaline Na2O, ZnO, SiO2, H2O system and noted for Mn-activated green luminescence and a strong piezoelectric effect. Single-crystal diffraction data…
The paper introduces elementary refinements of structural characterizability for semigroups in terms of first-order axiomatizability and elementary definability of their subsemigroup lattices. It proves general non-closure results for classes of such structures, including cases involving infinite cy…
This note constructs fundamental solutions for certain constant coefficient partial differential operators involving the singular Bessel operator in one variable. It introduces a basic test function space, generalized functions, convolution, translation, and the mixed Fourier-Bessel transform, then …
This paper examines the emergence of a second sound branch in a weakly nonideal Bose gas beyond the random-phase approximation. Starting from equations of motion for one-particle and density Green functions, the author introduces quasiparticle operators, derives a matrix Green function with interact…
This note addresses decision problems for finitely presented semigroups, with emphasis on constructing presentations with very few defining relations whose identity problem is undecidable. It proves that a semigroup on four generators with six defining relations has an unsolvable identity problem fo…
The paper addresses Nevanlinna’s conjecture that an entire function of finite order has only finitely many deficient values. It proves that for every sequence of complex numbers and every order greater than one half, there exists an entire function of that order, of normal type, for which all member…
This paper studies Cauchy problems for second-order differential equations in Banach spaces, covering abstract parabolic and hyperbolic equations with nonlinear terms. For parabolic equations, it uses resolvent estimates, fractional powers, and reduction to first-order systems to prove local existen…
This paper studies higher order approximations in the Bogolyubov, Krylov averaging method for ordinary differential equations with a small parameter, with the aim of weakening unnecessary smoothness and regularity assumptions used in earlier justifications. It introduces Hölder-type conditions for t…
This note studies well-posed solvability of the Cauchy problem for a linear evolution equation with variable coefficients on the real line, assuming that the highest coefficient is constant and the remaining coefficients converge at infinity to those of a constant-coefficient equation well-posed in …
This note studies nonlinear transformations of probability measures on functional spaces, motivated by determining the law of a transformed random process from the law of the input process. Working in a separable Hilbert space, it gives conditions under which the image measure induced by a measurabl…
This paper addresses the instability of Lyapunov characteristic exponents for nonautonomous linear systems under small perturbations and proposes a modified framework based on generalized, or limit, solutions. It defines the spectrum as the set of characteristic exponents of all generalized solution…
This paper develops a probabilistic model for crystallization of a semi-infinite multicomponent chain whose particles attach to and detach from the chain end with transition frequencies depending only on the terminal pair. It derives equations for the survival probabilities of chain configurations, …
This study investigates photodisintegration of the oxygen-16 nucleus, focusing on transition probabilities to several low-lying states of nitrogen-15 and on the total gamma absorption cross section above the giant resonance region. Photoproton energy spectra from the oxygen-16 gamma,p reaction were …
This paper develops a theory for the single-pulse operating regime of optical quantum generators that includes both the pulse-generation stage and the preceding accumulation of excitation energy in the active medium. It analyzes how amplified spontaneous emission shortens the effective excited-state…
The paper studies stationary subsets of metrizable spaces, understood via a compatible metric as sets that must meet the image of every sufficiently small continuous self-map. It proves that every finite-dimensional metrizable space contains a closed zero-dimensional stationary subset, using standar…
The paper presents a method for intermittent pneumatic computation based on the gas equation of state, using pneumatic capacitances to perform basic operations without complex mechanical computing devices. It develops the principle of a pulsating pneumatic resistance, in which alternating contact wi…
The paper introduces effective Phi-inseparability for two disjoint subsets of a metric space, extending earlier notions of effective non-enumerability and effective distinguishability. It defines inseparability through a continuous selection function on a compact metric base and studies how the prop…
This note gives a simplified proof, for the case \(lp>n\), of a theorem concerning the density of finitely supported functions in discrete Sobolev type spaces \(l_p^{(l)}\). Sobolev proves that if a function belongs to \(L_p^{(l)}(E_n)\), then its values on any regular lattice form an element of \(l…
The paper studies conditional extremal problems for real entire functions of finite exponential degree that are nonnegative on the real axis and belong to an Lp class, subject to admissible linear constraints. Using a Nikolskii type inequality and comparison with extremal problems in L1 and uniform …
This paper studies asymptotic formulas for the eigenvalue counting function of singular strongly elliptic differential operators with matrix-valued coefficients on unbounded domains. The approach relates the counting function to the trace of the Green matrix for an associated parabolic Cauchy proble…
This paper formulates the problem of a plane explosion in an ideally conducting perfect gas subject to an initially uniform magnetic field inclined at an arbitrary angle to the explosion plane. Using one-dimensional magnetohydrodynamic equations and shock-front jump conditions, it derives general sy…
This paper studies representations of topological semigroups as semigroups of continuous transformations, using the compact-open topology and related bicompact extensions. It proves that every topological semigroup is topologically isomorphic to a semigroup of continuous transformations of a topolog…
This paper reports measurements of the optical reflection spectra of ZnSiP2 single crystals at room temperature beyond the fundamental absorption edge, with the aim of obtaining information on their band structure. Using natural crystal surfaces and polarized as well as unpolarized incident radiatio…
The paper proves an undecidability result for a restricted fragment of the pure narrow predicate calculus with prenex formulas of the form involving a universal, existential, and universal quantifier prefix followed by an existential block. The argument reduces recursively inseparable halting and cy…
This paper investigates the fine structure of the scandium K-beta X-ray fluorescence emission spectrum in metallic scandium and in scandium diboride, carbide, nitride, and oxide, with the aim of relating spectral features to valence-band structure and chemical bonding. Using secondary excitation and…
The paper studies quasi-numbers and algorithms acting on them, introducing quasi-functions, their domains of definedness, and operators from quasi-numbers to quasi-numbers in a constructive setting. It proves that quasi-functions cannot have constructive discontinuities, using a lemma on the impossi…
This paper investigates weak anomalous luminescence that may arise from the second excited singlet state of chlorophyll-type molecules under intense ruby laser excitation. Solutions of chlorophyll a, chlorophyllin, methylchlorophyllide, and phthalocyanines were examined using filtered laser excitati…
This paper studies output controllability for linear nonstationary dynamic systems described by time-varying matrix equations with piecewise-continuous controls. It establishes equivalences between controllability conditions expressed through the fundamental matrix of the homogeneous system and cond…
This note studies normalized positive definite class functions on discrete nilpotent linear algebraic groups over a field of characteristic zero, with emphasis on describing the extreme points of this convex set. Using reductions to special nilpotent groups associated with Lie algebras of type gener…
This paper gives a criterion for the existence of time-periodic solutions of a quasilinear parabolic boundary value problem on a bounded domain, with coefficients and nonlinear terms periodic in time and satisfying ellipticity, Hölder, Lipschitz, and growth assumptions. The problem is formulated as …
This study examines the energy spectrum of radiation defects formed in n-type and p-type silicon single crystals after irradiation by gamma quanta, 1 MeV electrons, and fast reactor neutrons over a broad range of integral fluxes. The authors combine temperature dependences of conductivity and Hall c…
This paper studies the description of dual functors in categories of topological spaces with a distinguished point and in more general D-categories. For continuous functors on suitable categories of completely regular spaces, it proves that the dual functor is determined by its restriction to a smal…
This paper studies Lyapunov asymptotic stability of the zero solution for nonlinear differential equations in a Banach space with generally unbounded time-dependent linear operators. Using the Gateaux differentiability of the norm, it introduces one-sided estimates through the duality mapping and de…
This paper studies uniform approximation of continuous functions on simple Jordan arcs in complex Euclidean space by functions holomorphic on the arc. It proves that for a simple Jordan arc in complex two-space whose projection onto one coordinate is nowhere dense, every continuous function on the a…
