共查询到20条相似文献,搜索用时 187 毫秒
1.
Valentina Pepe 《Designs, Codes and Cryptography》2007,42(3):303-315
In this paper, we study the code which has as parity check matrix the incidence matrix of the design of the Hermitian curve and its (q + 1)-secants. This code is known to have good performance with an iterative decoding algorithm, as shown by Johnson and Weller
in (Proceedings at the ICEE Globe com conference, Sanfrancisco, CA, 2003). We shall prove that has a double cyclic structure and that by shortening in a suitable way it is possible to obtain new codes which have higher code-rate. We shall also present a simple way to constructing the matrix
via a geometric approach.
相似文献
2.
Peter L. Søndergaard 《Advances in Computational Mathematics》2007,27(4):355-373
By sampling the window of a Gabor frame for belonging to Feichtinger’s algebra, , one obtains a Gabor frame for . In this article we present a survey of results by R. Orr and A.J.E.M. Janssen and extend their ideas to cover interrelations
among Gabor frames for the four spaces , , and . Some new results about general dual windows with respect to sampling and periodization are presented as well. This theory
is used to show a new result of the Kaiblinger type to construct an approximation to the canonical dual window of a Gabor
frame for .
相似文献
3.
Mirjana Stojanović 《Acta Appl Math》2006,92(1):1-14
We consider several types of nonlinear parabolic equations with singular like potential and initial data. To prove the existence-uniqueness theorems we employ regularized derivatives. As a framework we use Colombeau space
and Colombeau vector space
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4.
We prove the following statement.
Let , and let . Suppose that, for all and , the sequence satisfies the relation
where e(u) : = e2πiu
.
Then
where
q is the set of q-multiplicative functions g such that . 相似文献
5.
Florian A. Potra 《Mathematical Programming》2008,111(1-2):243-272
Two corrector–predictor interior point algorithms are proposed for solving monotone linear complementarity problems. The algorithms
produce a sequence of iterates in the neighborhood of the central path. The first algorithm uses line search schemes requiring the solution of higher order polynomial
equations in one variable, while the line search procedures of the second algorithm can be implemented in arithmetic operations, where n is the dimension of the problems, is a constant, and m is the maximum order of the predictor and the corrector. If then both algorithms have iteration complexity. They are superlinearly convergent even for degenerate problems.
相似文献
6.
We have used different multivariate analysis methods to estimate quantities in the fields of food control and atmospheric
remote sensing. In order to estimate the uncertainties in these estimates we studied analytical as well as non-parametric
numerical methods. The methods have been evaluated by comparison between obtained results and independent sets of measurements.
We present one test case from each field, including results, where these methods have been applied. For the food control test
case reduced chi-squared of approximately unity indicate that both the analytical and numerical methods used for uncertainty estimation produce uncertainties
of reasonable size. In the atmospheric remote sensing test case, a indicated that the uncertainties from the numerical method were far too small, whereas a indicate that the size of the analytically determined uncertainties can represent the size of the “true” errors. 相似文献
7.
Let be a lattice of finite height. The correspondence between closure operators and ∧-subsemilattices is well known. Here we investigate what type of number-valued function is induces a ∧-subsemilattice ; and if so, what kind of . Conversely, what type of function is induced by what type of (or cl). Several results known for matroids, greedoids, or semimodular lattices are generalized. 相似文献
8.
Mika Hujo 《Journal of Theoretical Probability》2006,19(1):190-203
For a Borel-function
, we consider the approximation of a random variable f(W
1) with
by stochastic integrals with respect to the Brownian motion
and the geometric Brownian motion, where the integrands are piecewise constant within certain deterministic time intervals. In earlier papers it has been shown that under certain regularity conditions the optimal approximation rate is 1/
, if one optimizes over deterministic time-nets of cardinality n. We will show the existence of random variables f(W
1) such that the approximation error tends as slowly to zero as one wishes. 相似文献
9.
In this article we extend Milnor’s fibration theorem to the case of functions of the form with f, g holomorphic, defined on a complex analytic (possibly singular) germ (X, 0). We further refine this fibration theorem by looking not only at the link of , but also at its multi-link structure, which is more subtle. We mostly focus on the case when X has complex dimension two. Our main result (Theorem 4.4) gives in this case the equivalence of the following three statements:
Moreover one has that if these conditions hold, then the Milnor-Lê fibration of is a fibration of the multilink . We also give a combinatorial criterium to decide whether or not the multilink is fibered. If the meromorphic germ f/g is semitame, then we show that the Milnor-Lê fibration given by is equivalent to the usual Milnor fibration given by . We finish this article by discussing several realization problems.
Research partially supported by CONACYT and DGAPA-UNAM, Mexico, and by CNRS and ECOS, France. 相似文献
(i) | The real analytic germ has 0 as an isolated critical value; |
(ii) | the multilink is fibered; and |
(iii) | if is a resolution of the holomorphic germ , then for each rupture vertex (j) of the decorated dual graph of π one has that the corresponding multiplicities of f, g satisfy: . |
10.
A. Tiskin 《Journal of Mathematical Sciences》2009,158(5):759-769
Computation on compressed strings is one of the key approaches to processing massive data sets. We consider local subsequence
recognition problems on strings compressed by straight-line programs (SLP), which is closely related to Lempel–Ziv compression.
For an SLP-compressed text of length , and an uncompressed pattern of length n, Cégielski et al. gave an algorithm for local subsequence recognition running in time . We improve the running time to . Our algorithm can also be used to compute the longest common subsequence between a compressed text and an uncompressed pattern
in time ; the same problem with a compressed pattern is known to be NP-hard. Bibliography: 22 titles.
Published in Zapiski Nauchnykh Seminarov POMI, Vol. 358, 2008, pp. 282–300. 相似文献
11.
Yucheng Li 《Integral Equations and Operator Theory》2009,63(1):95-102
Let D be the unit disk and be the weighted Bergman space. In this paper, we prove that the multiplication operator is similar to
M
z
on .
The author was supported in part by NSF Grant (10571041, L2007B05). 相似文献
12.
Zhaoli Liu Jiabao Su Zhi-Qiang Wang 《Calculus of Variations and Partial Differential Equations》2009,35(4):463-480
In this paper, we study existence of nontrivial solutions to the elliptic equation
and to the elliptic system
where Ω is a bounded domain in with smooth boundary ∂Ω, , f (x, 0) = 0, with m ≥ 2 and . Nontrivial solutions are obtained in the case in which the nonlinearities have linear growth. That is, for some c > 0, for and , and for and , where I
m
is the m × m identity matrix. In sharp contrast to the existing results in the literature, we do not make any assumptions at infinity
on the asymptotic behaviors of the nonlinearity f and .
Z. Liu was supported by NSFC(10825106, 10831005). J. Su was supported by NSFC(10831005), NSFB(1082004), BJJW-Project(KZ200810028013)
and the Doctoral Programme Foundation of NEM of China (20070028004). 相似文献
13.
Christer Borell 《Probability Theory and Related Fields》2008,140(1-2):195-205
Let be an integer, let γ be the standard Gaussian measure on , and let . Given this paper gives a necessary and sufficient condition such that the inequality is true for all Borel sets A
1,...,A
m
in of strictly positive γ-measure or all convex Borel sets A
1,...,A
m
in of strictly positive γ-measure, respectively. In particular, the paper exhibits inequalities of the Brunn–Minkowski type
for γ which are true for all convex sets but not for all measurable sets.
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14.
Octavian G. Mustafa 《Annali di Matematica Pura ed Applicata》2008,187(2):187-196
Via an integral transformation, we establish two embedding results between the Emden-Fowler type equation , t ≥ t
0 > 0, with solutions x such that as , , and the equation , u > 0, with solutions y such that for given k > 0. The conclusions of our investigation are used to derive conditions for the existence of radial solutions to the elliptic
equation , , that blow up as in the two dimensional case.
相似文献
15.
Juncheng Wei Dong Ye Feng Zhou 《Calculus of Variations and Partial Differential Equations》2007,28(2):217-247
We consider the following anisotropic Emden–Fowler equation where is a bounded smooth domain and a(x) is a positive smooth function. We investigate the effect of anisotropic coefficient a(x) on the existence of bubbling solutions. We show that at given local maximum points of a(x), there exists arbitrarily many bubbles. As a consequence, the quantity can approach to
as . These results show a striking difference with the isotropic case [ Constant]. 相似文献
16.
Soogil Seo 《manuscripta mathematica》2008,127(3):381-396
A circular distribution is a Galois equivariant map ψ from the roots of unity μ
∞ to an algebraic closure of such that ψ satisfies product conditions, for ϵ ∈ μ
∞ and , and congruence conditions for each prime number l and with (l, s) = 1, modulo primes over l for all , where μ
l
and μ
s
denote respectively the sets of lth and sth roots of unity. For such ψ, let be the group generated over by and let be , where U
s
denotes the global units of . We give formulas for the indices and of and inside the circular numbers P
s
and units C
s
of Sinnott over .
This work was supported by the SRC Program of Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government
(MOST) (No. R11-2007-035-01001-0). This work was supported by the Korea Research Foundation Grant funded by the Korean Government
(MOEHRD, Basic Research Promotion Fund) (KRF-2006-312-C00455). 相似文献
17.
Sylvain Ervedoza 《Numerische Mathematik》2009,113(3):377-415
In this article, we derive uniform admissibility and observability properties for the finite element space semi-discretizations
of , where A
0 is an unbounded self-adjoint positive definite operator with compact resolvent. To address this problem, we present a new
spectral approach based on several spectral criteria for admissibility and observability of such systems. Our approach provides
very general admissibility and observability results for finite element approximation schemes of , which stand in any dimension and for any regular mesh (in the sense of finite elements). Our results can be combined with previous works to derive admissibility and observability
properties for full discretizations of . We also present applications of our results to controllability and stabilization problems.
The author was partially supported by the “Agence Nationale de la Recherche” (ANR), Project C-QUID, number BLAN-3-139579. 相似文献
18.
This paper deals with the stability of the intersection of a given set
with the solution,
, of a given linear system whose coefficients can be arbitrarily perturbed. In the optimization context, the fixed constraint
set X can be the solution set of the (possibly nonlinear) system formed by all the exact constraints (e.g., the sign constraints),
a discrete subset of
(as
or { 0,1}
n
, as it happens in integer or Boolean programming) as well as the intersection of both kind of sets. Conditions are given
for the intersection
to remain nonempty (or empty) under sufficiently small perturbations of the data.
Research supported by Fondecyt Grant 1020(7020)-646.
Research supported by DGES and FEDER, Grant BFM2002-04114-C02-01 相似文献
19.
Naoki Murabayashi 《Mathematische Annalen》2008,342(3):657-671
It is known that in the moduli space of elliptic curves, there exist precisely nine -rational points represented by an elliptic curve with complex multiplication by the maximal order of an imaginary quadratic
field. In Murabayashi and Umegaki (J Algebra 235:267–274, 2001) and Umegaki [Determination of all -rational CM-points in the moduli spaces of polarized abelian surfaces, Analytic number theory (Beijng/Kyoto, 1999). Dev.
Math., vol 6. Kluwer, Dordrecht, pp 349–357, 2002] we determined all -rational points in (the moduli space of d-polarized abelian surfaces) represented by a d-polarized abelian surface whose endomorphism ring is isomorphic to the maximal order of a quartic CM-field by using the result
in Murabayashi (J Reine Angew Math 470:1–26, 1996). In this paper, we prove that polarized abelian surfaces corresponding
to these -rational CM points have a -rational model by constructing certain Hecke characters. 相似文献
20.
Noboru Okazawa 《Mathematische Zeitschrift》2009,262(3):475-515
Several L
∞-estimates are obtained for in terms of and , where are determined by m. If p = 2, then the estimates are given with explicit constants. However, if p ≠ 2, it is difficult to derive explicit constants except in two simple cases. Applicability to PDE’s is illustrated. 相似文献