共查询到20条相似文献,搜索用时 31 毫秒
1.
O. V. Sarafanov 《Journal of Mathematical Sciences》2004,120(2):1195-1239
The C
*-algebra
generated by the operators of pseudodifferential boundary value problems on a manifold
with smooth closed disjoint edges and boundary
is studied. The operators act in the space L
2(
)
L
2(
). The goal of this paper is to describe all (up to an equivalence) irreducible representations of the algebra
Bibliography: 12 titles. 相似文献
2.
The paper deals with the problem of recovering the parameters (functions)
and
of the Maxwell dynamical system
(tan is the tangent component;
is a solution) by the response operator
(
is the normal). The parameters determine the velocity
, the c-metric
, and the time
. It is shown that for any fixed
, the operator
determines
and
in
uniquely. Bibliography: 15 titles. 相似文献
3.
S. Ya. Novikov 《Journal of Mathematical Sciences》2004,120(5):1733-1751
We study operators
(not necessarily linear) defined on a quasi-Bahach space X and taking values in the space of real-valued Lebesgue-measurable functions. Factorization theorems for linear and superlinear operators with values in the space
are proved with the help of the Lorentz sequence spaces
. Sequences of functions belonging to fixed bounded sets in the spaces
are characterized for
and
. The possibility of distinguishing weak type operators (bounded in the space
) from operators factorizable through
is obtained in terms of sequences of independent random variables. A criterion under which an operator is symmetrically bounded in order in
, is established. Some refinements of the above-mentioned results are obtained for translation shift-invariant sets and operators. Bibliography: 30 titles. 相似文献
4.
E. G. Emel'yanov 《Journal of Mathematical Sciences》2002,110(6):3078-3090
An extension of a theorem on extremal decomposition of a Riemann surface is obtained. The problem of extremal decomposition is extended from the case of a Riemann surface
with a prescribed set
of distinguished points to the case of the Teichmüller space
corresponding to
under quasiconformal homeomorphisms f. For the functional
of our problem on extremal decomposition of a surface
, we consider a function
expressing the dependence of the extremal value of
on a point
. Differentiation formulas for the function
are derived. These formulas are different and depend on the genus g of the surface
. The case where the function
is pluriharmonic is considered. Bibliography: 8 titles. 相似文献
5.
R. N. Karasev 《Journal of Mathematical Sciences》2001,104(4):1293-1300
Let
be a family of translations of a convex compact set
such that every two elements of
have a common point. Then there exist three points
such that each element of
contains one of these points. This answers in the affirmative an old question by Grünbaum. Bibliography: 13 titles. 相似文献
6.
M. B. Zvyagina 《Journal of Mathematical Sciences》2004,120(4):1591-1602
Let
be an associative ring with identity, and let
be the category of left unitary
-modules. A complete characterization of continuous additive co- and contravariant functors
is given. Such functors are either representable, or equivalent to a tensor product, or trivial ones. The class of categories that are dual to
and, therefore, are equivalent to the category of compact right
-modules is constructed by purely algebraic means. A canonical category is singled out in this class. A purely algebraic structure that is equivalent to the topology-algebraic structure of compact right
-modules is constructed. Algebraic analogs of connection and complete disconnection are given. Bibliography: 6 titles. 相似文献
7.
E. G. Goluzina 《Journal of Mathematical Sciences》2002,110(6):3052-3057
Let
be the class of functions satisfying the following conditions: these functions are regular and typically real in the unit disk, they have the form
, and the equality
holds for some fixed
and
with
. We find the set of values of the first two coefficients for functions from this class. Boundary functions for these sets of values are found. Some previous results of the author are supplemented. Boundary functions for the sets of values for the functionals
and
in the class
are found. Bibliography: 5 titles. 相似文献
8.
A. I. Generalov 《Journal of Mathematical Sciences》2004,120(4):1563-1574
A relative version of Rickard's theorem is proved, namely, if is a quasi-Frobenius proper class of short sequences in an Abelian category
, then the -stable category of the category
is a quotient category of the relative bounded derived category
(
). Bibliography: 20 titles. 相似文献
9.
G. V. Kuz'mina 《Journal of Mathematical Sciences》2003,118(1):4880-4894
We apply a variant of the method of the extremal metric to some problems concerning extremal decompositions and related problems. Let
be a system of distinct points on
and let
be the family of all systems
of nonoverlapping simply connected domains on
such that
. Let
where
is the reduced module of the domain
with respect to the point
. At present, the problem concerning the value
was solved completely for
. In this work, we continue the previous author's investigations and consider the case
. In addition, we consider the problem concerning the maximum of the sum
in the family
introduced above, where
, are arbitrary points of the circle
, and is a positive number. We prove that if
, then the maximum is attained only for systems of equidistant points of the circle
. For
, this result was obtained earlier by Dubinin who applied the method of symmetrization. It is shown that if
, where
is an even number, then equidistant points of the circle
do not realize the indicated maximum. Bibliography: 11 titles. 相似文献
10.
The Plücker embedding of the complex projective space
in the Grassmannian
of bivectors is used for proving several theorems on the relationship between the complex structure of
and its Riemannian geometry. It is shown that the separation set of
in the Plücker model is the face of
for a certain calibration. Bibliography: 11 titles. 相似文献
11.
V. O. Kuznetsov 《Journal of Mathematical Sciences》2003,118(1):4871-4879
We consider the function
, where
is the conformal radius of a simply connected domain D at a point
. We study relations between the values of the function
at various points of the domain D. In Sec. 1, we establish exact inequalities relating the values of the function
in an arbitrary simply connected domain
with the position of the conformal center and with the maximal conformal radius of the domain D. The same values are related to the values of
at another two points of the domain D. In Sec. 2, similar results are established for convex domains. This work supplements some recent results of Emel'yanov and Kovalev. Bibliography: 9 titles. 相似文献
12.
Masato Tomiyama 《Journal of Algebraic Combinatorics》1998,7(2):197-220
Let be a distance-regular graph with diameter
and height
, where
. Suppose that for every in and every in
, the induced subgraph on
is isomorphic to a complete multipartite graph
with
. Then
and is isomorphic to the Johnson graph
. 相似文献
13.
In the six-dimensional space
of bivectors, a Lie product similar to the standard vector product in
is introduced. The Lie algebra constructed is proved to be isomorphic to the Lie algebra of the orthogonal group
, and the isomorphism is a canonical isometry between
and the space of antisymmetric operators in
. Bibliography: 2 titles. 相似文献
14.
V.G. Osmolovskii 《Journal of Mathematical Sciences》2004,122(3):3278-3289
We consider the energy functional of a two-phase elastic medium
with quadratic energy densities
defined for
such that
,where
is a measurable characteristic function. Under some natural conditions on the data of the problem, we prove the existence of an interval (t
-,t
+) of the change of temperature
such that the energy functional has only a minimizer
such that
for
or
such that
t^ + $$
" align="middle" border="0">
. The energy functional has no minimizers
such that
or
if
. We derive two-sided estimates for the numbers
in terms of the characteristics of the two-phase elastic medium and the boundary condition. Bibliography: 3 titles. 相似文献
15.
O. L. Vinogradov 《Journal of Mathematical Sciences》2001,107(4):3987-4001
In what follows, C is the space of
-periodic continuous real-valued functions with uniform norm,
is the first continuity modulus of a function
with step h, H
n is the set of trigonometric polynomials of order at most n,
is the set of linear positive operators
(i.e., of operators such that
for every
),
is the space of square-integrable functions on
,
It is proved that
coincides with the smallest eigenvalue of some matrix of order n+1. The main result of the paper states that, for every
does not exceed and, for
, is equal to the minimum of the quadratic functional
over the unit sphere of
. Then it is calculated that
Bibliography: 19 titles. 相似文献
16.
M. S. Lyapina 《Journal of Mathematical Sciences》2004,120(2):1109-1116
A bi-Lipschitz continuous mapping of a space X is a bijection
such that
, where
. We write
if f is a Lipschitz (bi-Lipschitz) mapping of X into itself and denote by
the set of all bi-Lipschitz mappings of X that are not isometry. Thus,
if
and blip
. For X we consider a standard Cantor set K on the real line (with standard metric). The main result of this paper is formulated as follows:
where
Bibliography: 2 titles. 相似文献
17.
18.
A. N. Frolov 《Journal of Mathematical Sciences》2002,109(6):2229-2240
Let
be a sequence of independent equidistributed random vectors with
. Let
, where
and
denotes the indicator function of the event in brackets. If, for example,
are the gains and
are the indicators of success in repetitions of a game of chance, then
is the maximal gain along head runs (sequences of successes without interruptions) of length j. We investigate the asymptotic behavior of the values
,
, where
is the length of the longest head run in
. We show that the asymptotics of the values
depend significantly on the growth rate of j and that these asymptotics vary from the strong noninvariance (as in the ErdsRéenyi law of large numbers) to the strong invariance (as in the CsöorgRévész strong approximation laws). We also consider the Shepp-type statistics. Bibliography: 17 titles. 相似文献
19.
V. V. Makeev 《Journal of Mathematical Sciences》2003,113(6):812-815
A class of centrally-symmetric convex 12-topes (12-hedrons) in
is described such that for an arbitrary prescribed norm
on
each polyhedron in the class can be inscribed in (circumscribed about) the
-ball via an affine transformation, and this can be done with large degree of freedom. Bibliography: 5 titles. 相似文献
20.
L. Yu. Kolotilina 《Journal of Mathematical Sciences》2004,121(4):2465-2473
This paper studies irreducible matrices
, satisfying Brualdi's conditions
, or, shortly, Brualdi matrices. Here,
is the set of circuits of length
in the directed graph of A, and
is the support of
. Among the results obtained are a characterization of Brualdi matrices, implying, in particular, that they are generalized diagonally dominant; the necessary and sufficient conditions of singularity of Brualdi matrices; explicit expressions for the absolute values of the components of right null-vectors of a singular Brualdi matrix, and conditions necessary and sufficient for a boundary point of Brualdi's inclusion region to be an eigenvalue of an irreducible matrix. Bibliography: 8 titles. 相似文献