共查询到20条相似文献,搜索用时 15 毫秒
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Marc Chaperon Santiago López de Medrano José Lino Samaniego 《Comptes Rendus Mathematique》2005,340(11):827-832
Under fairly general hypotheses, we investigate by elementary methods the structure of the p-periodic orbits of a family of transformations near when and has a simple eigenvalue which is a primitive p-th root of unity. To cite this article: M. Chaperon et al., C. R. Acad. Sci. Paris, Ser. I 340 (2005). 相似文献
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Vladimir Shchigolev 《Journal of Algebra》2009,321(5):1453-1462
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Applying the frequency-uniform decomposition technique, we study the Cauchy problem for derivative Ginzburg–Landau equation , where , are complex constant vectors, , . For , we show that it is uniformly global well posed for all if initial data in modulation space and Sobolev spaces () and is small enough. Moreover, we show that its solution will converge to that of the derivative Schrödinger equation in if and in or with . For , we obtain the local well-posedness results and inviscid limit with the Cauchy data in () and . 相似文献
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A well-known cancellation problem of Zariski asks when, for two given domains (fields) and over a field k, a k-isomorphism of () and () implies a k-isomorphism of and . The main results of this article give affirmative answer to the two low-dimensional cases of this problem:1. Let K be an affine field over an algebraically closed field k of any characteristic. Suppose , then .2. Let M be a 3-dimensional affine algebraic variety over an algebraically closed field k of any characteristic. Let be the coordinate ring of M. Suppose , then , where is the field of fractions of A.In the case of zero characteristic these results were obtained by Kang in [Ming-chang Kang, A note on the birational cancellation problem, J. Pure Appl. Algebra 77 (1992) 141–154; Ming-chang Kang, The cancellation problem, J. Pure Appl. Algebra 47 (1987) 165–171]. However, the case of finite characteristic is first settled in this article, that answered the questions proposed by Kang in [Ming-chang Kang, A note on the birational cancellation problem, J. Pure Appl. Algebra 77 (1992) 141–154; Ming-chang Kang, The cancellation problem, J. Pure Appl. Algebra 47 (1987) 165–171]. 相似文献
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In this Note, we give sufficient conditions for the regularity of Leray–Hopf weak solutions to the Navier–Stokes equation. We prove that, if one of three conditions (i) where and , (ii) where and , or (iii) where and , is satisfied, then the solution is regular. These conditions improve earlier results on the conditional regularity of the Navier–Stokes equations. To cite this article: I. Kukavica, M. Ziane, C. R. Acad. Sci. Paris, Ser. I 343 (2006). 相似文献
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If is a tree then – T denotes the additive hereditary property consisting of all graphs that does not contain T as a subgraph. For an arbitrary vertex v of T we deal with a partition of T into two trees , , so that , , , , and . We call such a partition a of T. We study the following em: Given a graph G belonging to –T. Is it true that for any -partition , of T there exists a partition of the vertices of G such that and ? This problem provides a natural generalization of Δ-partition problem studied by L. Lovász ([L. Lovász, On decomposition of graphs. Studia Sci. Math. Hungar. 1 (1966) 237–238]) and Path Partition Conjecture formulated by P. Mihók ([P. Mihók, Problem 4, in: M. Borowiecki, Z. Skupien (Eds.), Graphs, Hypergraphs and Matroids, Zielona Góra, 1985, p. 86]). We present some partial results and a contribution to the Path Kernel Conjecture that was formulated with connection to Path Partition Conjecture. 相似文献
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Sarah Crown Rundell 《Journal of Combinatorial Theory, Series A》2012,119(5):1095-1109
In this paper, we study the homology of the coloring complex and the cyclic coloring complex of a complete k-uniform hypergraph. We show that the coloring complex of a complete k-uniform hypergraph is shellable, and we determine the rank of its unique nontrivial homology group in terms of its chromatic polynomial. We also show that the dimension of the homology group of the cyclic coloring complex of a complete k-uniform hypergraph is given by a binomial coefficient. Further, we discuss a complex whose r-faces consist of all ordered set partitions where none of the contain a hyperedge of the complete k-uniform hypergraph H and where . It is shown that the dimensions of the homology groups of this complex are given by binomial coefficients. As a consequence, this result gives the dimensions of the multilinear parts of the cyclic homology groups of . 相似文献
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We introduce regular expression constrained sequence alignment as the problem of finding the maximum alignment score between given strings and over all alignments such that in these alignments there exists a segment where some substring of is aligned to some substring of , and both and match a given regular expression R, i.e. where is the regular language described by R. For complexity results we assume, without loss of generality, that . A motivation for the problem is that protein sequences can be aligned in a way that known motifs guide the alignments. We present an time algorithm for the regular expression constrained sequence alignment problem where , and t is the number of states of a nondeterministic finite automaton N that accepts . We use in our algorithm a nondeterministic weighted finite automaton M that we construct from N. M has states where the transition-weights are obtained from the given costs of edit operations, and state-weights correspond to optimum alignment scores we compute using the underlying dynamic programming solution for sequence alignment. If we are given a deterministic finite automaton D accepting with states then our construction creates a deterministic finite automaton with states. In this case, our algorithm takes time. Using results in faster computation than using M when . If we only want to compute the optimum score, the space required by our algorithm is ( if we use a given ). If we also want to compute an optimal alignment then our algorithm uses space ( space if we use a given ) where and are substrings of and , respectively, , and and are aligned together in the optimal alignment that we construct. We also show that our method generalizes for the case of the problem with affine gap penalties, and for finding optimal regular expression constrained local sequence alignments. 相似文献
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Adam Paszkiewicz 《Comptes Rendus Mathematique》2009,347(19-20):1213-1216
We characterize sequences of numbers such that converges a.e. for any orthonormal system in any -space. To cite this article: A. Paszkiewicz, C. R. Acad. Sci. Paris, Ser. I 347 (2009). 相似文献