共查询到20条相似文献,搜索用时 31 毫秒
1.
E. S. Dubtsov 《Journal of Mathematical Sciences》2001,107(4):4002-4021
Let K be a compact space, let X be a closed subspace of C(K), and let
be a positive measure on K. The triple
is said to be regular if, for any positive function
and for any
, there exists a function
such that
on K and
. The case where K is the unit sphere in
and the subspace X is invariant with respect to the unitary group is investigated. Sufficient spectral conditions and a necessary condition for the regularity of a triple are obtained. Connections with compactness of certain Hankel operators and applications to interpolation problems are presented. Bibliography: 16 titles. 相似文献
2.
V. V. Makeev 《Journal of Mathematical Sciences》2002,110(4):2774-2775
Let A1,...,An be points in
, let
be a fixed point, let p be a positive integer, and let 1,...,n be positive real numbers. If the
does not depend on the position of M on a sphere with center O, then one says that the point system {A1,...,An} has an invariant of degree p with weight system {,...,n}. It is proved that for arbitrary positive integers d and N there exists a finite point system
having invariants of degrees p=1,...,N with common positive weight system {1,...,n}. Bibliography: 2 titles. 相似文献
3.
In this work the authors study the conditions for the existence of diffusion equations
in the cylinder Q = 3D ×
+,
n
, satisfying the homogeneous Dirichlet or Neumann conditions on the side boundary of the cylinder Q and decreasing with respect to t as a power for t . 相似文献
4.
Elliott H. Lieb 《Inventiones Mathematicae》1983,74(3):441-448
IfA andB are two bounded domains in
n
and (A), (B) are the lowest eigenvalues of – with Dirichlet boundary conditions then there is some translate,B
x, ofB such that (AB
x)<(A)+(B). A similar inequality holds for
.There are two corollaries of this theorem: (i) A lower bound for sup
x
{volume (AB
x)} in terms of (A), whenB is a ball; (ii) A compactness lemma for certain sequences inW
1,p
(
n
).Work partially supported by U.S. National Science Foundation grant PHY-8116101 A01. AMS(MOS) Classification: 35P15 相似文献
5.
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
6.
E. G. Emel'yanov 《Journal of Mathematical Sciences》1987,38(4):2081-2090
Let A={a1,...,an} and B={b1,...,bm} be systems of distinct points in
, let be a family of homotopic classes Hi,i=1,..., j+m, of closed Jordan curves on, where the classes Hj+l, l=1,...,m, consist of curves that are homotopic to a point curve in b. Let =1,..., j+m be a system of positive numbers and letU be the modulus of the extremal-metric problem for the family and the system . In this paper we investigate the dependence of the modulusU=U(,A,B) on the parameters i and on the disposition of the points ak and b. One shows thatU is a smooth function of the indicated arguments and one obtains expressions for the derivatives
U,
U, and
U. One gives some applications of these results.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 144, pp. 72–82, 1985. 相似文献
7.
A renormalization group transformation R
1 has a single stable point
in the space of the analytic circle homeomorphisms with a single cubic critical point and with the rotation number
(the golden mean). Let a homeomorphism T be the C
1-conjugate of
. We let
denote the sequence of distribution functions of the time of the kth entrance to the nth renormalization interval for the homeomorphism T. We prove that for any
, the sequence
has a finite limiting distribution function
, which is continuous in
, and singular on the interval [0,1]. We also study the sequence
for k>1. 相似文献
8.
9.
V. M. Badkov 《Mathematical Notes》1973,13(5):453-459
For the polynomials {pn(t)}
0
, orthonormalized on [–1, 1] with weightp(t) = (1–t) (1+t)
v=1
m
, we obtain necessary and sufficient conditions for boundedness of the sequences of norms: 1)
2)
and 3)
with the conditions that
on [–1, 1] and (H,)–1 L2(0, 2), where(H,) is the modulus of continuity in C(–1, 1) of function H.Translated from Matematicheskie Zametki, Vol. 13, No. 5, pp. 759–770, May, 1973. 相似文献
10.
ThisresearchissupportedbytheNationalNaturalScienceFoundationofChina.1.IntroductionInthispaper,weconsiderthefollowinginitial--boundaryvalueproblemwhereQ~fix(o,co),aQ=aflx(o,co),fiisaboundeddomaininEuclideanspaceR"(n22)withsmoothboundaryonandac=(u.,,'Iu..)denotesthegradientoffunctionu(x).Weassumethefunctionsal(x,t,u,p)(i=1,2,',n)anda(x,t,u,p)arelocallyH5ldercontinuousonfix(0,co)suchthatwherealtuandparepositiveconstants,m,aZIa3.hi,b2,alIadZ20,or321areconstants,m*E[0,m 2),hi16z/0,afl m*/… 相似文献
11.
A. A. Kon'kov 《Journal of Mathematical Sciences》2006,134(3):2073-2237
The paper considers solutions of the coercive inequalities
defined on an arbitrary (possibly, unbounded) subset ℝ
n
, where n ≥ 2, L and
are elliptic operators of the form
, and F is a certain function.
__________
Translated from Sovremennaya Matematika. Fundamental'nye Napravleniya (Contemporary Mathematics. Fundamental Directions),
Vol. 7, Partial Differential Equations, 2004. 相似文献
12.
Peter Hellekalek 《Monatshefte für Mathematik》1980,90(4):291-295
Ifp2 is an integer, then every nonnegative integerk is represented by an expression of the form
with integersa
i
(k), 0a
i
(k)p–1,i=0.1,...,s. The radical-inverse function to the basep,
p
(k), is defined by
. The sequence
is uniformly distributed modulo 1 (it may be called a one-dimensional Halton sequence). In the casep=2 it is the van der Corput sequence. The set of all numbers (0, 1] such that the local discrepancy
is bounded inn is determined. 相似文献
13.
Wilhelm Forst 《Numerische Mathematik》1978,30(2):137-147
Summary Letx
0<x
1<...<x
n–1<x
0+2 be nodes having multiplicitiesv
0,...,v
n–1, 1v
k
r (0k<n). We approximate the evaluation functional
,x fixed, and the integral respectively by linear functionals of the form
and determine optimal weights
for the Favard classesW
r
C
2. In the even case
of optimal interpolation these weights are unique except forr=1,x(x
k
+x
k–1)/2 mod 2. Moreover we get periodic polynomial splinesw
k, j
(0k<n, 0j<v
k
) of orderr such that
are the optimal weights. Certain optimal quadrature formulas are shown to be of interpolatory type with respect to these splines. For the odd case
of optimal interpolation we merely have obtained a partial solution.
Bojanov hat in [4, 5] ähnliche Resultate wie wir erzielt. Um Wiederholungen zu vermeiden, werden Resultate, deren Beweise man bereits in [4, 5] findet, nur zitiert 相似文献
14.
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
15.
Let
be a d - dimensional Markov family corresponding to a uniformly elliptic second order divergence form operator. We show that for any quasi continuous in the Sobolev space
the process (X) admits under P
x a decomposition into a martingale additive functional (AF) M
and a continuous AF A
of zero quadratic variation for almost every starting point x if q=2, for quasi every x if q>2 and for every
if is continuous, d=1 and
or d>1 and q>d. Our decomposition enables us to show that in the case of symmetric operator the energy of A
equals zero if q=2 and that the decomposition of (X) into the martingale AF M
and the AF of zero energy A
is strict if
for some q>d. Moreover, our decomposition provides a probabilistic representation of A
. 相似文献
16.
We study sets
there exist n projectors P1,...,Pn such that
. We prove that if n 6, then
. 相似文献
17.
We study Banach spaces of the form
We call such a space a p-space, p[1,), if for every k the space
is isomorphic to pk and the sequence (pk) strictly decreases to p. We examine the finite block representability of the spaces r in a p-space proving that it depends not only on p but also on the sequences (pk) and (nk). Assuming that i ni
1/q decreases to 0, where q is the conjugate exponent of p, we prove the existence of an asymptotic biorthogonal system in X and also that c
0 is finitely representable in X. Moreover we investigate the modified versions of p-spaces proving that, if nkm1/pkm-1/pkm-1 increases to infinity for a subsequence (nkm) , then 1 embeds into X. We also investigate complemented minimality for the class of spaces
where
is either a subsequence of the sequence of Schreier classes (
n)n N or a subsequence of (
n)n N. 相似文献
18.
Marko Huhtanen 《BIT Numerical Mathematics》2003,43(3):563-570
In this note it is shown that any square matrix AC
n×n
can be represented as the sum A=
, where
is complex symmetric and rank
. The corresponding persymmetric result can be used in finding the terms of a small rank perturbed Toeplitz matrix via an O(n
2) computation. This allows one to perform fast matrix–vector products in case n is large. 相似文献
19.
Define
, where
is a symmetric U-type statistic, H
k() is the Hermite polynomial of degree k, and {X, X
n, n1} are independent identically distributed binary random variables with Pr(X{–1, 1}})=1. We show that
according as EX=0 or EX0, respectively. 相似文献
20.
Ryszard Grząślewicz 《Monatshefte für Mathematik》1990,110(3-4):257-259
LetN
1,N
be thel
1 andl
norms on
n
. We denote by
the set of all normsN on
n
such thatN
NN
1. The aim of the paper is to present a characterization of the extreme points of
.This paper has been written while the author was a research fellow of the Alexander von Humboldt-Stiftung at the Mathematisches Institut der Eberhardt-Karls-Universität, Tübingen. 相似文献