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991.
Abstract. We propose C
1
Hermite interpolants generated by the general subdivision scheme introduced by Merrien [17] and satisfying monotonicity
or convexity constraints. For arbitrary values and slopes of a given function f at the end-points of a bounded interval, which are compatible with the contraints, the given algorithms construct shape-preserving
interpolants. Moreover, these algorithms are quite simple and fast as well as adapted to CAGD. We also give error estimates
in the case of interpolation of smooth functions. 相似文献
992.
M. G. Betti V. Corradini V. De Renzi C. Mariani P. Casarini A. Abramo 《Solid State Communications》1999,110(12):661-666
We present high energy-resolution photoemission measurements of the spectral density at the discrete quantized electronic levels of a two-dimensional (2D) electron gas. The dynamical 2D electron gas has been obtained by generating a strong accumulation layer at the (110) surface of narrow-gap III–V semiconductors. Exploitation of a number of cases generating band bending (metallic chains or clusters, atomic structure, defects) demonstrates the generality of 2D electron gas formation at charge-accumulated semiconductor surfaces. A self-consistent solution of the Poisson and Schrödinger equations gives the potential well shape, the sub-band energy level position and the accumulated charge density, in excellent agreement with the present experimental data. 相似文献
993.
A group G is said to satisfy the maximal permutizer condition if the permutizer of any maximal subgroup M of G in G, PG(M), is G. In this paper, we characterize the supersolubility of finite groups by using the maximal permutizer condition. We also get some results for when both G/N and N are supersoluble, which implies that G is supersoluble. Our results unify or generalize some known results. 相似文献
994.
Jonas T. Hartwig 《Journal of Pure and Applied Algebra》2008,212(4):863-883
We derive necessary and sufficient conditions for an ambiskew polynomial ring to have a Hopf algebra structure of a certain type. This construction generalizes many known Hopf algebras, for example U(sl2), Uq(sl2) and the enveloping algebra of the three-dimensional Heisenberg Lie algebra. In a torsion-free case we describe the finite-dimensional simple modules, in particular their dimensions, and prove a Clebsch-Gordan decomposition theorem for the tensor product of two simple modules. We construct a Casimir type operator and prove that any finite-dimensional weight module is semisimple. 相似文献
995.
L. Bernal-González M. C. Calderón-Moreno J. A. Prado-Bassas 《Integral Equations and Operator Theory》2008,60(1):1-11
The existence of infinite dimensional closed linear spaces of holomorphic functions f on a domain G in the complex plane such that Tf has dense images on certain subsets of G, where T is a continuous linear operator, is analyzed. Necessary and sufficient conditions for T to have the latter property are provided and applied to obtain a number of concrete examples: infinite order differential
operators, composition operators and multiplication operators, among others.
This work was supported in part by the Plan Andaluz de Investigación de la Junta de Andalucía FQM-127 and by MEC DGES Grants
MTM2006-13997-C02-01 and MTM2004-21420-E. 相似文献
996.
Ragnar-Olaf Buchweitz 《Advances in Mathematics》2008,217(1):205-242
We introduce Hochschild (co-)homology of morphisms of schemes or analytic spaces and study its fundamental properties. In analogy with the cotangent complex we introduce the so-called (derived) Hochschild complex of a morphism; the Hochschild cohomology and homology groups are then the Ext and Tor groups of that complex. We prove that these objects are well defined, extend the known cases, and have the expected functorial and homological properties such as graded commutativity of Hochschild cohomology and existence of the characteristic homomorphism from Hochschild cohomology to the (graded) centre of the derived category. 相似文献
997.
Miles Holloway 《Archiv der Mathematik》2008,90(4):311-316
We answer a question raised in [9] by showing the equality of two different definitions of rank variety for finitely generated
modules over truncated polynomial algebras. We do this by establishing an isomorphism of algebras used in the two definitions
of rank variety.
Received: 23 April 2007 相似文献
998.
单片机在设计性物理实验中的应用 总被引:2,自引:0,他引:2
在设计性物理实验中引入单片机技术 ,使学生了解怎样实现测量数字化与自动化 ,初步掌握信号放大、数据采集、编程等基本方法 相似文献
999.
André Diatta 《Differential Geometry and its Applications》2008,26(5):544-552
Amongst other results, we perform a ‘contactization’ method to construct, in every odd dimension, many contact Lie groups with a discrete center, unlike the usual (classical) contactization which only produces Lie groups with a non-discrete center. We discuss some applications and consequences of such a construction, construct several examples and derive some properties. We give classification results in low dimensions. A complete list is supplied in dimension 5. In any odd dimension greater than 5, there are infinitely many locally non-isomorphic solvable contact Lie groups. We also characterize solvable contact Lie algebras whose derived ideal has codimension one. For simplicity, most of the results are given in the Lie algebra version. 相似文献
1000.
I. Hoteit 《国际流体数值方法杂志》2008,58(11):1181-1199
Four‐dimensional variational data assimilation in meteorology and oceanography suffers from the presence of local minima in the cost function. These local minima arise when the system under study is strongly nonlinear. The number of local minima further dramatically increases with the length of the assimilation period and often renders the solution to the problem intractable. Global optimization methods are therefore needed to resolve this problem. However, the huge computational burden makes the application of these sophisticated techniques unfeasible for large variational data assimilation systems. In this study, a Simulated Annealing (SA) algorithm, complemented with an order‐reduction of the control vector, is used to tackle this problem. SA is a very powerful tool of combinatorial minimization in the presence of several local minima at the cost of increasing the execution time. Order‐reduction is then used to reduce the dimension of the search space in order to speed up the convergence rate of the SA algorithm. This is achieved through a proper orthogonal decomposition. The new approach was implemented with a realistic eddy‐permitting configuration of the Massachusetts Institute of Technology general circulation model (MITgcm) of the tropical Pacific Ocean. Numerical results indicate that the reduced‐order SA approach was able to efficiently reduce the cost function with a reasonable number of function evaluations. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献