Showing 50 of 5847 papers in Mathematics

SOME PROPERTIES OF GENERALIZED SOLUTIONS OF SECOND-ORDER PARABOLIC EQUATIONS

A. V. Ivanov, O. A. Ladyzhenskaya, A. L. Treskunov, N. N. Ural'tseva
1966 SovietRxiv: ru-196601.40090

This paper studies generalized solutions of second order uniformly parabolic linear and quasilinear equations using mixed space time norms to describe coefficient and data integrability. It develops a level set lemma for functions satisfying Caccioppoli type inequalities, yielding power, exponential…

New Books

A. R. Shakun
1966 SovietRxiv: ru-196601.39818

This bibliographic notice surveys recently published mathematical books and teaching materials available in 1965 and 1966, primarily from Soviet academic and educational presses. The entries cover monographs, textbooks, lecture notes, handbooks, and collected papers in differential equations, mathem…

ON CLOSED IDEALS IN A LOCALLY CONVEX ALGEBRA OF ENTIRE FUNCTIONS WITH AN ARBITRARY GROWTH MAJORANT

I. F. Krasichkov
1966 SovietRxiv: ru-196601.39793

This paper studies a locally convex algebra of entire functions whose growth is controlled by an arbitrary increasing majorant satisfying a logarithmic convexity condition. The author defines a natural topology on this algebra, establishes continuity of multiplication, and analyzes closed ideals thr…

Traces of elliptic operators on submanifolds and $K$-theory

Corresponding Member of the Academy of Sciences of the USSR S. P. NOVIKOV, B. Yu. STERNIN
1966 SovietRxiv: ru-196601.39570

This paper studies Dirichlet Sobolev problems for elliptic operators on closed manifolds with trace data imposed on submanifolds, and asks how the resulting change in analytic index can be computed. Using Atiyah Singer characteristic classes, Todd classes, Euler classes, symmetric and exterior power…

…with a deviating argument. (Peoples’ Friendship University named after P. Lumumba), 1965, 3, pp. 249–251.

Unknown
1966 SovietRxiv: ru-196601.39413

This item is a bibliographic and editorial notice from a 1966 issue of Differential Equations. It lists recent 1965 publications in differential equations, mathematical physics, numerical analysis, stability theory, boundary value problems, and related areas, giving authors, titles, journal details,…

A CRITERION FOR THE CORRECTNESS OF A UNIFORM SPACE

A. G. Mordkovich
1966 SovietRxiv: ru-196601.39079

The paper addresses V. A. Efremovich’s problem of characterizing when a general uniform space, defined by symmetric binary relations interpreted as orders of nearness, induces a proximity satisfying the standard nearness axioms. It proves a necessary and sufficient criterion consisting of three cond…

Statistical Properties of a Nonlinear String

F. M. Izrailev, B. V. Chirikov
1966 SovietRxiv: ru-196601.38993

The paper examines the onset of statistical, or stochastic, behavior in longitudinal oscillations of a nonlinear string with fixed ends, modeled as a finite chain of nonlinear oscillators related to the Fermi, Pasta, and Ulam problem. By transforming to normal coordinates and treating the nonlinear …

ON A CLASS OF SINGULAR INTEGRAL EQUATIONS

A. Yanushauskas
1966 SovietRxiv: ru-196601.38621

This paper studies a class of singular integral equations on the unit sphere in three-dimensional Euclidean space, with Hölder-continuous coefficients and data. By introducing spherical coordinates, expanding the unknown and right-hand side in trigonometric series, and reducing the problem to one-di…

ON THE UNSOLVABILITY OF THE WORD IDENTITY PROBLEM FOR ONE CLASS OF SEMIGROUPS WITH A SOLVABLE ISOMORPHISM PROBLEM

E. I. Grindlinger
1966 SovietRxiv: ru-196601.38262

The paper studies decision problems for the class K1 of finitely presented semigroups whose defining words do not occur inside distinct defining words. It constructs a 15-generator semigroup in this class containing a Tseitin semigroup as a subsemigroup, thereby showing that K1 includes a semigroup …

CONDITIONS ON A SET, NECESSARY AND SUFFICIENT IN ORDER THAT EVERY CONTINUOUS FUNCTION ANALYTIC AT ITS INTERIOR POINTS ADMIT UNIFORM APPROXIMATION BY RATIONAL FUNCTIONS

A. G. Vitushkin
1966 SovietRxiv: ru-196601.38042

This note studies when the algebra of functions continuous on a closed bounded plane set and analytic at its interior points coincides with the uniform closure on that set of rational functions with poles off the set. Using a new approximation scheme based on partitions of unity and estimates involv…

ON THE NATURE OF THE DEPENDENCE OF SOLUTIONS OF CERTAIN HYPERBOLIC EQUATIONS ON THE INITIAL FUNCTIONS

L. G. Gromova
1966 SovietRxiv: ru-196601.38035

This note studies how solutions of certain constant coefficient hyperbolic equations depend on initial data on the base of the characteristic cone, with emphasis on the existence of lacunae and weak lacunae. For strictly hyperbolic equations in two independent variables, it proves a necessary and su…

ON ONE CASE OF A DISCONTINUOUS RIEMANN PROBLEM

A. D. Alekseev
1966 SovietRxiv: ru-196601.37527

The paper studies a discontinuous Riemann boundary value problem on simple closed rectifiable curves of class K, with coefficients and free terms belonging to integral Hölder classes. It establishes auxiliary results on products of such functions, proves a Poincaré-Bertrand formula for Cauchy type s…

HAUSDORFF SPACES OF MINIMAL WEIGHT

W. Holsztyński
1966 SovietRxiv: ru-196601.36926

This paper introduces Hausdorff spaces of minimal weight, defined by the requirement that every open cover separating points has cardinality at least the weight of the space. It gives equivalent and sufficient conditions for this property, proves that Tychonoff products of spaces of minimal weight a…

EQUIVALENCE OF TWO CLASSES OF MAPPINGS OF THE SPHERE

V. P. Kompaniets, A. V. Chernavskii
1966 SovietRxiv: ru-196601.36794

This note studies self-maps of the n-dimensional sphere whose point preimages are cellular, motivated by the relation between such maps and maps approximable by homeomorphisms. It proves that, for n not equal to 4, every pointlike mapping of the sphere onto itself is cellular, meaning that the preim…

ON GAUSSIAN MEASURES EQUIVALENT TO GAUSSIAN MARKOV MEASURES

Yu. I. Golosov
1966 SovietRxiv: ru-196601.36682

This note studies criteria for equivalence, orthogonality, and strong equivalence of Gaussian measures on spaces of real functions, focusing on cases where one measure is generated by a Wiener process or by a Gaussian Markov process. Using reproducing kernel Hilbert spaces and the operator criterion…

EMBEDDING THEOREMS FOR THE SPACES \(W_{p_0\bar p}^{(\bar l)}\), \(B_{p_0\bar\theta}^{(\bar l)}\)

A. D. BERIEV
1966 SovietRxiv: ru-196601.36655

The paper proves embedding theorems for the spaces W and B with mixed norms and anisotropic smoothness parameters, allowing the orders of smoothness to be arbitrary positive numbers. It first establishes weighted integral inequalities for kernels defined by anisotropic metrics in products of Euclide…

INVESTIGATION OF GENERAL BOUNDARY-VALUE PROBLEMS FOR PARABOLIC EQUATIONS BY THE METHOD OF DIFFERENTIAL EQUATIONS IN A BANACH SPACE

P. E. Sobolevskii
1966 SovietRxiv: ru-196601.36606

This paper develops an abstract Banach space method for studying boundary value problems for parabolic equations whose associated elliptic operators have domains depending on time, as occurs with variable boundary conditions. The main result establishes the existence and properties of an evolution o…

ON BOREL SETS IN PERFECTLY NORMAL BICOMPACTS

V. I. Ponomarev
1966 SovietRxiv: ru-196601.36319

This note proves that in every uncountable perfectly normal bicompact space, each countable Hausdorff Borel class below the first uncountable ordinal is nonempty. The argument reduces to spaces without isolated points, uses a continuous surjection onto an interval, and establishes a key factorizatio…

HOMOLOGIES OF SPACES OF SMOOTH EMBEDDINGS

A. S. Schwarz
1966 SovietRxiv: ru-196601.35892

This note studies the homology of spaces of smooth embeddings of a compact smooth manifold into another smooth manifold in the high codimension range, especially for based embeddings. It develops exact sequences and spectral sequences by filtering spaces of immersions according to singularity type, …

ON DEGENERATE HYPERGEOMETRIC FUNCTIONS OF HUMBERT AND HORN

M. B. Kapilevich
1966 SovietRxiv: ru-196601.35662

The paper studies the confluent hypergeometric functions of Humbert and Horn, especially the series H3 and Xi2, in connection with the generalized wave equation with singular coefficient. It derives integral relations, inverse formulas, limiting transitions, addition and expansion theorems, and redu…

NECESSARY AND SUFFICIENT CONDITIONS FOR THE STABILIZATION OF THE SOLUTION OF THE CAUCHY PROBLEM

V. D. Repnikov, S. D. Èidel'man
1966 SovietRxiv: ru-196601.35168

This paper studies pointwise stabilization as time tends to infinity for solutions of the Cauchy problem for parabolic equations, beginning with higher order constant coefficient equations generated by powers of the Laplacian. Using Wiener’s Tauberian theorem and analysis of the Fourier transforms o…

A GENERALIZATION OF THE THEOREMS OF CARTER AND WIELANDT

Ya. G. Berkovich
1966 SovietRxiv: ru-196601.34794

This note generalizes two results in finite group theory associated with Carter and Wielandt. It introduces auxiliary lemmas on Carter subgroups, the Carter property, Hall subgroups, and abnormal subgroups, and proves that a pi-solvable group has the Carter property when all its pi-prime subgroups h…

On Factor Representations of Anticommutation Relations

V. Ya. Golodets
1966 SovietRxiv: ru-196601.33578

This paper studies factor representations of the canonical anticommutation relations in separable Hilbert spaces, using a measure-theoretic realization based on diagonalizing the commuting number projections. It proves that factor representations require an ergodic quasi-invariant measure, analyzes …

ON THE REGULARIZATION OF THE SUPREMUM OF A FAMILY OF PLURISUBHARMONIC FUNCTIONS AND ITS APPLICATION TO ANALYTIC FUNCTIONS OF SEVERAL VARIABLES

L. I. Ronkin
1966 SovietRxiv: ru-196601.33207

The paper studies regularization of the supremum and upper limit of families of plurisubharmonic functions that are uniformly bounded above in domains of complex Euclidean space. Extending a theorem of H. Cartan, it proves that the exceptional sets where these functions differ from their upper semic…

ON THE APPROXIMATION OF FUNCTIONS OF THE CLASSES \(W_p^\alpha\) BY PIECEWISE-POLYNOMIAL FUNCTIONS

M. Sh. Birman, M. Z. Solomyak
1966 SovietRxiv: ru-196601.32628

The paper studies approximation of functions in Sobolev, Slobodetskii spaces by piecewise polynomial functions on cube partitions, under the continuity condition alpha p greater than the dimension. It proves sharp order estimates for uniform approximation and for approximation in Lq with respect to …

ON A GENERALIZATION OF PROJECTION METHODS

N. I. Pol'skii
1966 SovietRxiv: ru-196601.32357

The paper develops a generalization of projection methods for solving operator equations in which trial functions need not satisfy either the differential expression or boundary conditions in advance. It formulates the problem in a Hilbert space direct sum, treating the interior operator and boundar…