共查询到20条相似文献,搜索用时 234 毫秒
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本文利用箭图和拓扑伪紧空间研究了K-余代数及其表示.定义了域K上的伪紧K-余代数,研究了伪紧K-余代数和K-代数范畴之间的关系,研究了余挠对和余模逼近,描述了余倾斜余挠对.通过有限维的支撑子余代数和基本的路余代数研究了弦余代数. 相似文献
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作者在弱幂等完备的正合范畴(A,ε)中引入了复形的新的定义,并且证明了ε-正合复形的同伦范畴κex(ε)是同伦范畴κε(A)的厚子范畴.给定(A,ε)中的余挠对(x,y),定义了正合范畴(cε(A),C(ε))中的两个余挠对(x~ε,dgy~ε)和(dgx~ε,y~ε),并且证明了当A是可数完备时,cε(A)中任意无界复形的dgx~ε,y~ε-分解存在.作为应用,建立了相对于范畴κex(ε)和Dε(A)的范畴κ_ε(A)的左粘合,给出了R-模范畴的粘合的例子. 相似文献
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我们在本文中引入了Abel范畴的右双-Giraud粘合定义.我们证明了右双-Giraud粘合与余遗传和遗传的挠对存在着双射对应.此外,我们通过模范畴中特定的幂等理想刻画了这类挠对. 相似文献
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本文证明了f-余倾斜余模的Bongartz引理,即一个偏f-余倾斜余模可以做成f-余倾斜余模.首先得到了f-余倾斜余模的性质以及C-余模和AT-模之间的函子同构.此外还研究了Hom-挠对和Hom-余倾斜余模. 相似文献
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引进了相对于一个双模ω的ω-k-挠自由模,用左addR ω-逼近刻画了ω-k-挠自由模. 引进了ω-左逼近维数,描述了是k-挠自由模的k-合冲模的形式. 相似文献
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熊涛 《纯粹数学与应用数学》2021,37(2):167-175
研究了Milnor方图上的余挠维数,然后探讨了环的余挠维数和整体维数,弱整体维数之间的关系和差别.证明了一个Prüfer整环的余挠维数不超过1当且仅当它是整体维数不超过2的Matlis整环. 相似文献
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引进了相对于一个双模 ω-的ω-k-挠自由模,用左addR ω-逼近刻画了ω-k-挠自由模.引进了 ω-左逼近维数,描述了是k-挠自由模的k-合冲模的形式. 相似文献
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De Xu Zhou 《数学学报(英文版)》2009,25(9):1567-1582
Assume that S is an almost excellent extension of R. Using functors HomR(S,-) and -×R S, we establish some connections between classes of modules lR and lS, cotorsion pairs (AR, BR) and (AS, BS). If lS is a T-extension or (and) H-extension of lR, we show that lS is a (resp., monomorphic, epimorphic, special) preenveloping class if and only if so is lR. If (AS, BS) is a TH- extension of (AR, BR), we obtain that (AS, BS) is complete (resp., of finite type, of cofinite type, hereditary, perfect, n-tilting) if and only if so is (AR, BR). 相似文献
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《Discrete Applied Mathematics》2004,134(1-3):239-261
An asteroidal triple (AT) is a set of vertices such that each pair of vertices is joined by a path that avoids the neighborhood of the third. Every AT-free graph contains a dominating pair, a pair of vertices such that for every path between them, every vertex of the graph is within distance one of the path. We say that a graph is a hereditary dominating pair (HDP) graph if each of its connected induced subgraphs contains a dominating pair. In this paper we introduce the notion of frame HDP graphs in order to capture the structure of HDP graphs that contain asteroidal triples. We also determine the maximum diameter of frame HDP graphs. 相似文献
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Ya-nan LIN & Lin XIN Department of Mathematics Xiamen University Xiamen China Department of Mathematics Fujian Normal University Puzhou China 《中国科学A辑(英文版)》2007,50(1):13-26
Motivated by the concept of a torsion pair in a pre-triangulated category induced by Beligiannis and Reiten, the notion of a left (right) torsion pair in the left (right) triangulated category is introduced and investigated. We provide new connections between different aspects of torsion pairs in one-sided triangulated categories, pre-triangulated categories, stable categories and derived categories. 相似文献
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Hong Oh Kim Rae Young Kim Jae Kun Lim Zuowei Shen 《Journal of Approximation Theory》2007,147(2):196-204
We start with a characterization of a pair of frames to be orthogonal in a shift-invariant space and then give a simple construction of a pair of orthogonal shift-invariant frames. This is applied to obtain a construction of a pair of Gabor orthogonal frames as an example. This is also developed further to obtain constructions of a pair of orthogonal wavelet frames. 相似文献
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The weighted matroid parity problems for the matching matroid and gammoids are among the very few cases for which the weighted matroid parity problem is polynomial time solvable. In this work we extend these problems to a general revenue function for each pair, and show that the resulting problem is still solvable in polynomial time via a standard weighted matching algorithm. We show that in many other directions, extending our results further is impossible (unless P = NP). One consequence of the new polynomial time algorithm is that it demonstrates, for the first time, that a prize-collecting assignment problem with “pair restriction” is solved in polynomial time. The prize collecting assignment problem is a relaxation of the prize-collecting traveling salesman problem which requires, for any prescribed pair of nodes, either both nodes of the pair are matched or none of them are. It is shown that the prize collecting assignment problem is equivalent to the prize collecting cycle cover problem which is hence solvable in polynomial time as well. 相似文献
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Harry Dym 《Integral Equations and Operator Theory》1978,1(2):152-175
In this paper we shall study the Fredholm determinant and related trace formulas for a class of operators which correspond to the restriction of integral operators with kernels of the form k(x,y) = (x)gv(x–y)+[1–(x)]fv(x–y) to the square |x|,|y| T and shall evaluate the limit as T . Here denotes the indicator function of the right half-line [0,) . The results obtained generalize the well known formulas of M. Kac for the classical convolution operator in which g = f . 相似文献
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We say that a sequence \(\left( x_n\right) _{n \ge 1}\) in [0, 1) has Poissonian pair correlations if for all \(s>0\). In this note we show that if the convergence in the above expression is—in a certain sense—fast, then this implies a small discrepancy for the sequence \(\left( x_n\right) _{n \ge 1}\). As an easy consequence it follows that every sequence with Poissonian pair correlations is uniformly distributed in [0, 1).
相似文献
$$\begin{aligned} \lim _{N \rightarrow \infty } \frac{1}{N} \# \left\{ 1 \le l \ne m \le N{:}\,\left||x_l-x_m\right|| < \frac{s}{N} \right\} = 2s \end{aligned}$$
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Stefan Steinerberger 《Indagationes Mathematicae》2018,29(5):1167-1178
A sequence on the torus is said to exhibit Poissonian pair correlation if the local gaps behave like the spacings of a Poisson random variable, i.e. We show that being close to Poissonian pair correlation for few values of is enough to deduce global regularity statements: if, for some , a set of points satisfies then the discrepancy of the set satisfies . We also show that distribution properties are reflected in the global deviation from the Poissonian pair correlation where the lower bound is conditioned on . The proofs use a connection between exponential sums, the heat kernel on
and spatial localization. Exponential sum estimates are obtained as a byproduct. We also describe a connection to diaphony and several open problems. 相似文献
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We use the degeneration formula and the absolute/relative correspondence tostudy the change of stable pair invariants of threefold under blow-ups and obtain some closed blow-up formulae, which imply some interesting relations among BPS state counts. Our results provide positive evidence for the GW/DT/P correspondence, and also give a partial correspondence for varieties not necessarily toric or complete intersections. 相似文献