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1.
Introduce the notation:
, is the union of two segments [-1,1] and [-1 +
,1+
],
is a noninteger number,
is the Hölder class with exponent
on
The following result announced by the authors in [J. Math. Sci. 117 (2003), No. 3] is proved. There exist numbers a
1 (
) , b
1 (
)
0 depending only on
such that for any
there exists a polynomial
, such that
. Bibliography: 11 titles. 相似文献
2.
The C*-algebra
generated by the Bergman and anti-Bergman projections and by the operators of multiplication by piecewise continuous functions on the Lebesgue space L2(Π) over the upper half-plane is studied. Making use of a local principle, limit operators techniques, and the Plamenevsky results on two-dimensional singular integral operators with coefficients admitting homogeneous discontinuities we reduce the study to simpler C*-algebras associated with points
and pairs
We construct a symbol calculus for unital C*-algebras generated by n orthogonal projections sum of which equals the unit and by m one-dimensional orthogonal projections. Such algebras are models of local algebras at points z ∈∂Π being the discontinuity points of coefficients. A symbol calculus for the C*- algebra
and a Fredholm criterion for the operators
are obtained. Finally, a C*-algebra isomorphism between the quotient algebra
where
is the ideal of compact operators, and its analogue
for the unit disk is constructed. 相似文献
3.
Let G be a finite group,
a normal subgroup, p a prime,
a finite splitting field of characteristic p for
G and
We prove that
is a splitting field for N, using the action
of the Galois group of the field extension
on the irreducible representations of N.
As
is a splitting field for the symmetric group
Sn
we get as a corollary that
is a splitting field for the alternating group
An.
Received: 31 July 2003 相似文献
4.
We use the Temperley-Lieb algebra to define a family of totally nonnegative polynomials of the form
. The cone generated by these polynomials contains all totally nonnegative polynomials of the form
, where,
are matrix minors. We also give new conditions on the sets I,...,K′ which characterize differences of products of minors which are totally nonnegative.
Received September 30, 2004 相似文献
5.
Suppose that k and l are integers such that
and
, M
k is a set of numbers without kth powers, and
. In this paper, we obtain asymptotic estimates of the sums
over
相似文献
6.
The systems of bases are constructed for the spaces of cusp forms
and
. Formulas are obtained for the number of representations of a positive integer by the sum of k binary quadratic forms of the kind
, of the kind
and of the kind
. 相似文献
7.
We give the asymptotics of the sum
, where
, for the multiplicative functions
, and
. 相似文献
8.
We give a new proof of the Jung-Abhyankar theorem: Let
an algebraically closed field of characteristic 0, be a Weierstraß polynomial with discriminant
where U is a unit; then its roots are fractionary power series.
Received: 17 December 1999 相似文献
9.
The optimal value function
of the quadratic program
, where
is a given symmetric matrix,
a given matrix,
and
are the linear perturbations, is considered. It is proved that
is directionally differentiable at any point
in its effective domain
. Formulae for computing the directional derivative
of
at
in a direction
are obtained. We also present an example showing that, in general,
is not piecewise linear-quadratic on W. The preceding (unpublished) example of Klatte is also discussed. 相似文献
10.
We show that every sub-weak embedding of any singular (degenerate or not) orthogonal or unitary polar space of non-singular rank at least 3 in a projective space PG
,
a commutative field, is the projection of a full embedding in some subspace PG
of PG
, where PG
contains PG
and
is a subfield of
. The same result is proved in the symplectic case under the assumption that the field over which the polarity is defined is perfect if the characteristic is 2 and if each secant line of the embedded polar space contains exactly two points of . This completes the classification of all sub-weak embeddings of orthogonal, symplectic and unitary polar spaces (singular or not; degenerate or not) of non-singular rank at least 3 and defined over a commutative field
, where in the characteristic 2 case
is perfect if the polar space is symplectic and the degree of the embedding is 2. 相似文献
11.
In this work we determine the group of modular automorphisms of the
Drinfeld modular curve
for any nonconstant polynomial
.Received: 19 September 2002 相似文献
12.
Let X be a rearrangement-invariant Banach function space
over a complete probability space
, and denote by
the Hardy space consisting of all martingales
such that
. We prove that
implies
for any filtration
if and only if Doobs inequality holds in
X, where
denotes the martingale defined by
, n = 0, 1, 2, ..., and
a.s.Received: 1 August 2000 相似文献
13.
In this paper the set of minimal periods of periodic points of
1-norm nonexpansive maps
is studied. This set is denoted by R(n). The main goal is to
present a characterization of R(n) by arithmetical and
combinatorial constraints. More precisely, it is shown that
, where
denotes the set of periods of
restricted admissible arrays on 2n
symbols. The important point of this equality is that
is determined by
arithmetical and combinatorial constraints only, and that it can
be computed in finite time. By using this equality the set R(n)
is computed for
. Furthermore it is shown that the largest element
of
R(n) satisfies:
相似文献
14.
Let p be a prime number.
Let G be a finite
p-group and
. Denote by
the complex conjugate of
. Assume that
. We show that the number of
distinct irreducible constituents of the product
is at least
.
Received: 17 March 2003 相似文献
15.
Consider the Schrödinger operator
with a complex-valued
potential v of period
Let
and
be the eigenvalues of L that are close to
respectively, with periodic (for n even),
antiperiodic (for n odd), and Dirichelet
boundary conditions on [0,1], and let
be the diameter of the spectral
triangle with vertices
We prove the following statement: If
then v(x) is a Gevrey function, and moreover
相似文献
16.
The goal of this paper is to extend some previous results on abelian ideals of Borel subalgebras to so-called spherical ideals of
These are ideals
of
such that their G-saturation
is a spherical G-variety. We classify all maximal spherical ideals of
for all simple G.Received: 25 March 2004 相似文献
17.
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
18.
Asymptotic Normality for Non-linear Functionals of Non-causal Linear Processes with Summable Weights
Let
be a non-causal linear process with weights ajs satisfying certain summability conditions, and the iid sequence of innovation {i} having zero mean and finite second moment. For a large class of non-linear functional K which includes indicator functions and polynomials, the present paper develops the
central limit theorem for the partial sums
相似文献
19.
N. A. Shirokov 《Journal of Mathematical Sciences》2004,124(2):4935-4939
Let
, where the
and
satisfy the following relations:
and
. Denote by B
the class of all entire functions of exponential type bounded on the real axis. Under certain assumptions on the rate of approximation on E of a bounded function f by functions in B
( varies), we get some information about the smoothness of f. Bibliography: 4 titles. 相似文献
20.
A. Cossidente J. W. P. Hirschfeld G. Korchmáros F. Torres 《Compositio Mathematica》2000,121(2):163-181
The number N of rational points on an algebraic curve of genus g over a finite field
satisfies the Hasse–Weil bound
. A curve that attains this bound is called maximal. With
and
, it is known that maximalcurves have
. Maximal curves with
have been characterized up to isomorphism. A natural genus to be studied is
and for this genus there are two non-isomorphic maximal curves known when
. Here, a maximal curve with genus g
2 and a non-singular plane model is characterized as a Fermat curve of degree
. 相似文献