共查询到20条相似文献,搜索用时 954 毫秒
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Caio De Naday Hornhardt Helen Samara Dos Santos Mikhail Kochetov 《Journal of Pure and Applied Algebra》2019,223(4):1590-1616
We classify gradings by arbitrary abelian groups on the classical simple Lie superalgebras , , and on the simple associative superalgebras , , over an algebraically closed field: fine gradings up to equivalence and G-gradings, for a fixed group G, up to isomorphism. As a corollary, we also classify up to isomorphism the G-gradings on the classical Lie superalgebra that are induced from G-gradings on . In the case of Lie superalgebras, the characteristic is assumed to be 0. 相似文献
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Let k be a field and let Λ be an indecomposable finite dimensional k-algebra such that there is a stable equivalence of Morita type between Λ and a self-injective split basic Nakayama algebra over k. We show that every indecomposable finitely generated Λ-module V has a universal deformation ring and we describe explicitly as a quotient ring of a power series ring over k in finitely many variables. This result applies in particular to Brauer tree algebras, and hence to p-modular blocks of finite groups with cyclic defect groups. 相似文献
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Alan Koch Timothy Kohl Paul J. Truman Robert Underwood 《Journal of Pure and Applied Algebra》2019,223(5):2230-2245
Let be a finite separable extension of fields whose Galois closure has Galois group G. Greither and Pareigis use Galois descent to show that a Hopf algebra giving a Hopf–Galois structure on has the form for some group N of order . We formulate criteria for two such Hopf algebras to be isomorphic as Hopf algebras, and provide a variety of examples. In the case that the Hopf algebras in question are commutative, we also determine criteria for them to be isomorphic as K-algebras. By applying our results, we complete a detailed analysis of the distinct Hopf algebras and K-algebras that appear in the classification of Hopf–Galois structures on a cyclic extension of degree , for p an odd prime number. 相似文献
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《Journal of Pure and Applied Algebra》2019,223(11):5030-5048
Take positive integers m, n and d. Let Y be an m-fold cyclic cover of ramified over a general hypersurface of degree md. In this paper we study the space of lines in Y and show that it is smooth of dimension if and . When , our result gives a formula on the number of m-contact order lines of X (see Definition 1.2). 相似文献
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Andrea Pasquali 《Journal of Pure and Applied Algebra》2019,223(8):3537-3553
If A and B are n- and m-representation finite k-algebras, then their tensor product is not in general -representation finite. However, we prove that if A and B are acyclic and satisfy the weaker assumption of n- and m-completeness, then Λ is -complete. This mirrors the fact that taking higher Auslander algebra does not preserve d-representation finiteness in general, but it does preserve d-completeness. As a corollary, we get the necessary condition for Λ to be -representation finite which was found by Herschend and Iyama by using a certain twisted fractionally Calabi–Yau property. 相似文献
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《Journal of Pure and Applied Algebra》2019,223(11):4966-4993
We introduce a type affine C analogue of the nil Temperley–Lieb algebra, in terms of generators and relations. We show that this algebra , which is a quotient of the positive part of a Kac–Moody algebra of type , has an easily described faithful representation as an algebra of creation and annihilation operators on particle configurations, reminiscent of the open TASEP model in statistical physics. The centre of consists of polynomials in a certain element Q, and is a free module of finite rank over its centre. We show how to localize by adjoining an inverse of Q, and prove that the resulting algebra is a full matrix ring over a ring of Laurent polynomials over a field. Although has wild representation type, over an algebraically closed field we can classify all the finite dimensional indecomposable representations of in which Q acts invertibly. 相似文献
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We consider non-degenerate graph immersions into affine space whose cubic form is parallel with respect to the Levi-Civita connection of the affine metric. There exists a correspondence between such graph immersions and pairs , where J is an n-dimensional real Jordan algebra and γ is a non-degenerate trace form on J. Every graph immersion with parallel cubic form can be extended to an affine complete symmetric space covering the maximal connected component of zero in the set of quasi-regular elements in the algebra J. It is an improper affine hypersphere if and only if the corresponding Jordan algebra is nilpotent. In this case it is an affine complete, Euclidean complete graph immersion, with a polynomial as globally defining function. We classify all such hyperspheres up to dimension 5. As a special case we describe a connection between Cayley hypersurfaces and polynomial quotient algebras. Our algebraic approach can be used to study also other classes of hypersurfaces with parallel cubic form. 相似文献
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《Applied and Computational Harmonic Analysis》2020,48(1):46-63
There is a finite number of tight frames of n distinct vectors for which are the orbit of a vector under a unitary action of the cyclic group . These cyclic harmonic frames (or geometrically uniform tight frames) are used in signal analysis and quantum information theory, and provide many tight frames of particular interest. Here we investigate the conjecture that grows like . By using a result of Laurent which describes the set of solutions of algebraic equations in roots of unity, we prove the asymptotic estimate By using a group theoretic approach, we also give some exact formulas for , and estimate the number of cyclic harmonic frames up to projective unitary equivalence. 相似文献
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Zachary Cline 《Journal of Pure and Applied Algebra》2019,223(8):3635-3664
Let q be an nth root of unity for and let be the Taft (Hopf) algebra of dimension . In 2001, Susan Montgomery and Hans-Jürgen Schneider classified all non-trivial -module algebra structures on an n-dimensional associative algebra A. They further showed that each such module structure extends uniquely to make A a module algebra over the Drinfel'd double of . We explore what it is about the Taft algebras that leads to this uniqueness, by examining actions of (the Drinfel'd double of) Hopf algebras H “close” to the Taft algebras on finite-dimensional algebras analogous to A above. Such Hopf algebras H include the Sweedler (Hopf) algebra of dimension 4, bosonizations of quantum linear spaces, and the Frobenius–Lusztig kernel . 相似文献
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Charles Almeida Aline V. Andrade Rosa M. Miró-Roig 《Journal of Pure and Applied Algebra》2019,223(4):1817-1831
Let be a minimal monomial Togliatti system of forms of degree d. In [4], Mezzetti and Miró-Roig proved that the minimal number of generators of lies in the interval . In this paper, we prove that for and , the integer values in cannot be realized as the number of minimal generators of a minimal monomial Togliatti system. We classify minimal monomial Togliatti systems of forms of degree d with or 3n (i.e. with the minimal number of generators reaching the border of the non-existence interval). Finally, we prove that for , and there exists a minimal monomial Togliatti system of forms of degree d with . 相似文献
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《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