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991.
The concept of pure gaps of a Weierstrass semigroup at several points of an algebraic curve has been used lately to obtain
codes that have a lower bound for the minimum distance which is greater than the Goppa bound. In this work, we show that the
existence of total inflection points on a smooth plane curve determines the existence of pure gaps in certain Weierstrass
semigroups. We then apply our results to the Hermitian curve and construct codes supported on several points that compare
better to one-point codes from that same curve.
相似文献
992.
We develop the perturbation theory for propagators, with the objective to prove Gaussian bounds. Let U be a strongly continuous propagator, i.e., a family of operators describing the solutions of a non-autonomous evolution equation, on an Lp-space, and assume that U is positive and satisfies Gaussian upper and lower bounds. Let V be a (time-dependent) potential satisfying certain Miyadera conditions with respect to U. We show that then the perturbed propagator enjoys Gaussian upper and lower bounds as well. To prepare the necessary tools, we extend the perturbation theory of strongly continuous propagators and the theory of absorption propagators. 相似文献
993.
In this paper, by using a fixed point theorem for condensing multi-valued maps, we have investigated the existence of mild solutions for a class of semilinear impulsive neutral functional differential inclusions with nonlocal conditions. As an application, an example has been presented to illustrate the results obtained. 相似文献
994.
This article is concerned with the ill-posed Cauchy problem associated with a densely defined linear operator A in a Banach space. A family of weak regularizing operators is introduced. If the spectrum of A is contained in a sector of right-half complex plane and its resolvent is polynomially bounded, the weak regularization for such ill-posed Cauchy problem can be shown by using the quasi-reversibility method and regularized semigroups. Finally, an example is given. 相似文献
995.
曹六川 《数学物理学报(B辑英文版)》2006,26(2):246-254
This article introduces the concept of commutative semigroups of almost asymptotically nonexpansive-type mappings in a Banach space X which has the Opial property and whose norm is UKK, and establishes the weak convergence theorems for almost-orbits of this class of commutative semigroups. The author improves, extends and develops some recent and earlier results. 相似文献
996.
Ebru Ozbilge 《Mathematical Methods in the Applied Sciences》2008,31(11):1333-1344
In this article, a semigroup approach is presented for the mathematical analysis of the inverse coefficient problems of identifying the unknown diffusion coefficient k(u(x, t)) in the quasi‐linear parabolic equation ut(x, t)=(k(u(x, t))ux(x, t))x, with Dirichlet boundary conditions ux(0, t)=ψ0, u(1, t)=ψ1. The main purpose of this work is to analyze the distinguishability of the input–output mappings Φ[·] : ??→C1[0, T], Ψ[·] : ??→C1[0, T] using semigroup theory. In this article, it is shown that if the null space of semigroups T(t) and S(t) consists of only a zero function, then the input–output mappings Φ[·] and Ψ[·] have the distinguishability property. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
997.
An extension of the Perron-Frobenius Theorem is presented in the much more general setting of indecomposable semigroups of nonnegative matrices. Many features of the original theorem including the existence of a fixed positive vector, a block-monomial form, and spectral stability properties hold simultaneously for these semigroups. The paper is largely self-contained and the proofs are elementary. The classical theorem and some related results follow as corollaries. 相似文献
998.
We establish the existence of bounded, almost periodic and asymptotically almost periodic mild solutions for first- and second-order abstract-retarded functional differential equations with unbounded delay. 相似文献
999.
A new method for the construction of Fock-adapted quantum stochastic operator cocycles is outlined, and its use is illustrated
by application to a number of examples arising in physics and probability. The construction uses the Trotter-Kato theorem
and a recent characterisation of such cocycles in terms of an associated family of contraction semigroups.
In celebration of Kalyan Sinha’s sixtieth birthday 相似文献
1000.
Windowing Waveform Relaxation of Initial Value Problems 总被引:2,自引:0,他引:2
Yao-lin Jiang 《应用数学学报(英文版)》2006,22(4):575-588
We present a windowing technique of waveform relaxation for dynamic systems.An effectiveestimation on window length is derived by an iterative error expression provided here.Relaxation processes canbe speeded up if one takes the windowing technique in advance.Numerical experiments are given to furtherillustrate the theoretical analysis. 相似文献