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921.
本文定义了一个由范畴 RMRl到范畴A Grn0 的函子G,并证明了函子G保持分量正合及全正合,关于范畴AGGrn0 证明了定理: 相似文献
922.
Summary. Motivated by a hedging problem in mathematical finance, El Karoui and Quenez [7] and Kramkov [14] have developed optional
versions of the Doob-Meyer decomposition which hold simultaneously for all equivalent martingale measures. We investigate
the general structure of such optional decompositions, both in additive and in multiplicative form, and under constraints
corresponding to different classes of equivalent measures. As an application, we extend results of Karatzas and Cvitanić [3]
on hedging problems with constrained portfolios.
Received: 6 August 1996/In revised form: 5 March 1997 相似文献
923.
Marco Grandis 《Applied Categorical Structures》1994,2(4):351-406
We develop here a version of abstract homotopical algebra based onhomotopy kernels andcokernels, which are particular homotopy limits and colimits. These notions are introduced in anh-category, a sort of two-dimensional context more general than a 2-category, abstracting thenearly 2-categorical properties of topological spaces, continuous maps and homotopies. A setting which applies also, at different extents, to cubical or simplicial sets, chain complexes, chain algebras, ... and in which homotopical algebra can be established as a two-dimensional enrichment of homological algebra.Actually, a hierarchy of notions ofh-,h1-, ...h4-categories is introduced, through progressive enrichment of thevertical structure of homotopies, so that the strongest notion,h4-category, is a sort of relaxed 2-category. After investigating homotopy pullbacks and homotopical diagrammatical lemmas in these settings, we introduceright semihomotopical categories, ash-categories provided with terminal object and homotopy cokernels (mapping cones), andright homotopical categories, provided also with anh4-structure and verifying second-order regularity properties forh-cokernels.In these frames we study the Puppe sequence of a map, its comparison with the sequence of iterated homotopy cokernels and theh-cogroup structure of the suspension endofunctor. Left (semi-) homotopical categories, based on homotopy kernels, give the fibration sequence of a map and theh-group of loops. Finally, the self-dual notion of homotopical categories is considered, together with their stability properties.Lavoro esequito nell'ambito dei progetti di ricerca del MURST. 相似文献
924.
Key pathways of interaction between growing radicals of vinyl monomers and bis(cyclopentadienyl) derivatives of Group IV–VI
transition metal dichlorides were studied by the BP86/6-31G(d) and B3LYP/LanL2DZ quantum chemical methods. Prospects for use
of these organometallic compounds as chain growth regulators in controlled polymerization were assessed. The character of
the interaction of the compounds studied with the growing radicals is mainly determined by the metal atom.
Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1690–1694, September, 2007. 相似文献
925.
回顾了域上典型群的生成问题所得成果,对局部环上典型群生成问题的研究,作了一个展示,并按展示的范式,给出了辛群生成定理的证明. 相似文献
926.
An algebra A over a field k is FCR if every finite dimensional representation of A is completely reducible and the intersection of the kernels of these representations is zero. We give a useful characterization
of FCR-algebras and apply this to C
*-algebras and to localizations. Moreover, we show that “small” products and sums of FCR-algebras are again FCR.
Received: 25 October 2000 相似文献
927.
Ying‐Tong Di Ling‐Li Liu Chun‐Shun Li Yu Zhang Qiang Zhang Shu‐Zhen Mu Qian‐Yun Sun Fu‐Mei Yang Hai‐Yang Liu Xiao‐Jiang Hao 《Helvetica chimica acta》2008,91(5):838-843
Eight C30 Daphniphyllum alkaloids, including two new ones, yunnandaphninines F and G ( 1 and 2 , resp.), were isolated from the leaves and stems of Daphniphyllum yunnanense. Their structures were elucidated on the basis of the spectroscopic data. 相似文献
928.
For a left pure semisimple ring R, it is shown that the local duality establishes a bijection between the preinjective left R-modules and the preprojective right R-modules, and any preinjective left R-module is the source of a left almost split morphism. Moreover, if there are no nonzero homomorphisms from preinjective modules to non-preinjective indecomposable modules in R-mod, the direct sum of all non-preinjective indecomposable direct summands of products of preinjective left R-modules is a finitely generated product-complete module. This generalizes a recent theorem of Angeleri Hügel [L. Angeleri Hügel, A key module over pure-semisimple hereditary rings, J. Algebra 307 (2007) 361-376] for hereditary rings. 相似文献
929.
Nikolaos M. Missirlis 《Numerische Mathematik》1984,45(3):447-458
Summary A variety of iterative methods considered in [3] are applied to linear algebraic systems of the formAu=b, where the matrixA is consistently ordered [12] and the iteration matrix of the Jacobi method is skew-symmetric. The related theory of convergence is developed and the optimum values of the involved parameters for each considered scheme are determined. It reveals that under the aforementioned assumptions the Extrapolated Successive Underrelaxation method attains a rate of convergence which is clearly superior over the Successive Underrelaxation method [5] when the Jacobi iteration matrix is non-singular. 相似文献
930.
Sufficient conditions are given for linear processes and ARMA processes to have the Gaswirth and Rubin mixing condition. The mixing rates are also determined. 相似文献