共查询到20条相似文献,搜索用时 15 毫秒
1.
《Journal of Pure and Applied Algebra》2021,225(12):106773
Graded-division algebras are building blocks in the theory of finite-dimensional associative algebras graded by a group G. If G is abelian, they can be described, using a loop construction, in terms of central simple graded-division algebras.On the other hand, given a finite abelian group G, any central simple G-graded-division algebra over a field is determined, thanks to a result of Picco and Platzeck, by its class in the (ordinary) Brauer group of and the isomorphism class of a G-Galois extension of .This connection is used to classify the simple G-Galois extensions of in terms of a Galois field extension with Galois group isomorphic to a quotient and an element in the quotient subject to certain conditions. Non-simple G-Galois extensions are induced from simple T-Galois extensions for a subgroup T of G. We also classify finite-dimensional G-graded-division algebras and, as an application, finite G-graded-division rings. 相似文献
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《Discrete Mathematics》2023,346(1):113126
New s-extremal extremal unimodular lattices in dimensions 38, 40, 42 and 44 are constructed from self-dual codes over by Construction A. In the process of constructing these codes, we obtain a self-dual code over . In addition, the code implies a code over . These codes have larger minimum weights than the previously known codes and codes, respectively. 相似文献
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We construct invariant polynomials on truncated multicurrent algebras, which are Lie algebras of the form , where is a finite-dimensional Lie algebra over a field of characteristic zero, and I is a finite-codimensional ideal of generated by monomials. In particular, when is semisimple and is algebraically closed, we construct a set of algebraically independent generators for the algebra of invariant polynomials. In addition, we describe a transversal slice to the space of regular orbits in . As an application of our main result, we show that the center of the universal enveloping algebra of acts trivially on all irreducible finite-dimensional representations provided I has codimension at least two. 相似文献
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Alex Iosevich Chun-Kit Lai Azita Mayeli 《Applied and Computational Harmonic Analysis》2019,46(1):192-205
Let be an integer, and , , be the vector space over the cyclic space . The purpose of this paper is two-fold. First, we obtain sufficient conditions on such that the inverse Fourier transform of generates a tight wavelet frame in . We call these sets (tight) wavelet frame sets. The conditions are given in terms of multiplicative and translational tilings, which is analogous with Theorem 1.1 ([20]) by Wang in the setting of finite fields. In the second part of the paper, we exhibit a constructive method for obtaining tight wavelet frame sets in , , q an odd prime and (mod 4). 相似文献
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Julia Semikina 《Journal of Pure and Applied Algebra》2019,223(10):4509-4523
I. Hambleton, L. Taylor and B. Williams conjectured a general formula in the spirit of H. Lenstra for the decomposition of for any finite group G and noetherian ring R. The conjectured decomposition was shown to hold for some large classes of finite groups. D. Webb and D. Yao discovered that the conjecture failed for the symmetric group , but remarked that it still might be reasonable to expect the HTW-decomposition for solvable groups. In this paper we show that the solvable group is also a counterexample to the conjectured HTW-decomposition. Nevertheless, we prove that for any finite group G the rank of does not exceed the rank of the expression in the HTW-decomposition. We also show that the HTW-decomposition predicts correct torsion for for any finite group G. Furthermore, we prove that for any degree other than the conjecture gives a correct prediction for the rank of . 相似文献
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We give methods for constructing many self-dual -codes and Type II -codes of length 2n starting from a given self-dual -code and Type II -code of length 2n, respectively. As an application, we construct extremal Type II -codes of length 24 for and extremal Type II -codes of length 32 for . We also construct new extremal Type II -codes of lengths 56 and 64. 相似文献
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In this work we give a characterization of Galois Linear Complementary Dual codes and Galois-invariant codes over mixed alphabets of finite chain rings, which leads to the study of the Gray image of -linear codes, where and that provides LCD codes over . 相似文献
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The notion of multiple Ore extension is introduced as a natural generalization of Ore extensions and double Ore extensions. For a PBW-deformation of type quantum group, we explicitly obtain the commutation relations of its root vectors, then show that it can be realized via a series of multiple Ore extensions, which we call a ladder Ore extension of type . Moreover, we analyze the quantum algebras with of type , and and give some examples and counterexamples that can be realized by a ladder Ore extension. 相似文献
15.
Lukas Katthän 《Journal of Pure and Applied Algebra》2019,223(3):1227-1245
Let be a squarefree monomial ideal in a polynomial ring. In this paper we study multiplications on the minimal free resolution of . In particular, we characterize the possible vectors of total Betti numbers for such ideals which admit a differential graded algebra (DGA) structure on . We also show that under these assumptions the maximal shifts of the graded Betti numbers are subadditive.On the other hand, we present an example of a strongly generic monomial ideal which does not admit a DGA structure on its minimal free resolution. In particular, this demonstrates that the Hull resolution and the Lyubeznik resolution do not admit DGA structures in general.Finally, we show that it is enough to modify the last map of to ensure that it admits the structure of a DG algebra. 相似文献
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Judit Abardia-Evéquoz Károly J. Böröczky Mátyás Domokos Dávid Kertész 《Journal of Functional Analysis》2019,276(11):3325-3362
The space of continuous, -equivariant, , and translation covariant valuations taking values in the space of real symmetric tensors on of rank is completely described. The classification involves the moment tensor valuation for and is analogous to the known classification of the corresponding tensor valuations that are -equivariant, although the method of proof cannot be adapted. 相似文献
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Let be a finite group. It was remarked in Breuillard et al. (2015) that if the Cayley graph is an expander graph and is non-bipartite then the spectrum of the adjacency operator is bounded away from . In this article we are interested in explicit bounds for the spectrum of these graphs. Specifically, we show that the non-trivial spectrum of the adjacency operator lies in the interval , where denotes the (vertex) Cheeger constant of the regular graph with respect to a symmetric set of generators and . 相似文献
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We introduce an altered version of the four circulant construction over group rings for self-dual codes. We consider this construction over the binary field, the rings and ; using groups of order 4 and 8. Through these constructions and their extensions, we find binary self-dual codes of lengths 16, 32, 48, 64 and 68, many of which are extremal. In particular, we find forty new extremal binary self-dual codes of length 68, including twelve new codes with in , which is the first instance of such a value in the literature. 相似文献
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《Stochastic Processes and their Applications》2020,130(9):5492-5509
In the Constrained-degree percolation model on a graph there are a sequence, , of i.i.d. random variables with distribution and a positive integer . Each bond tries to open at time , it succeeds if both its end-vertices would have degrees at most . We prove a phase transition theorem for this model on the square lattice , as well as on the d-ary regular tree. We also prove that on the square lattice the infinite cluster is unique in the supercritical phase. 相似文献