共查询到20条相似文献,搜索用时 62 毫秒
1.
Diogo Diniz Claudemir Fidelis Bezerra Júnior 《Journal of Pure and Applied Algebra》2018,222(6):1388-1404
Let F be an infinite field. The primeness property for central polynomials of was established by A. Regev, i.e., if the product of two polynomials in distinct variables is central then each factor is also central. In this paper we consider the analogous property for and determine, within the elementary gradings with commutative neutral component, the ones that satisfy this property, namely the crossed product gradings. Next we consider , where R admits a regular grading, with a grading such that is a homogeneous subalgebra and provide sufficient conditions – satisfied by with the trivial grading – to prove that has the primeness property if does. We also prove that the algebras satisfy this property for ordinary central polynomials. Hence we conclude that, over a field of characteristic zero, every verbally prime algebra has the primeness property. 相似文献
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Marcel Herzog Patrizia Longobardi Mercede Maj 《Journal of Pure and Applied Algebra》2018,222(7):1628-1642
Denote the sum of element orders in a finite group G by and let denote the cyclic group of order n. Suppose that G is a non-cyclic finite group of order n and q is the least prime divisor of n. We proved that and . The first result is best possible, since for each , k odd, there exists a group G of order n satisfying and the second result implies that if G is of odd order, then . Our results improve the inequality obtained by H. Amiri, S.M. Jafarian Amiri and I.M. Isaacs in 2009, as well as other results obtained by S.M. Jafarian Amiri and M. Amiri in 2014 and by R. Shen, G. Chen and C. Wu in 2015. Furthermore, we obtained some -based sufficient conditions for the solvability of G. 相似文献
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One of the most frequently referenced monographs on power series rings, “Power Series over Commutative Rings” by James W. Brewer, states in Theorem 21 that if M is a non-SFT maximal ideal of a commutative ring R with identity, then there exists an infinite ascending chain of prime ideals in the power series ring , such that for each n. Moreover, the height of is infinite. In this paper, we show that the above theorem is false by presenting two counter examples. The first counter example shows that the height of can be zero (and hence there is no chain of prime ideals in satisfying for each n). In this example, the ring R is one-dimensional. In the second counter example, we prove that even if the height of is uncountably infinite, there may be no infinite chain of prime ideals in satisfying for each n. 相似文献
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Jan O. Kleppe 《Journal of Pure and Applied Algebra》2018,222(3):610-635
Let be the scheme parameterizing graded quotients of with Hilbert function H (it is a subscheme of the Hilbert scheme of if we restrict to quotients of positive dimension, see definition below). A graded quotient of codimension c is called standard determinantal if the ideal I can be generated by the minors of a homogeneous matrix . Given integers and , we denote by the stratum of determinantal rings where are homogeneous of degrees .In this paper we extend previous results on the dimension and codimension of in to artinian determinantal rings, and we show that is generically smooth along under some assumptions. For zero and one dimensional determinantal schemes we generalize earlier results on these questions. As a consequence we get that the general element of a component W of the Hilbert scheme of is glicci provided W contains a standard determinantal scheme satisfying some conditions. We also show how certain ghost terms disappear under deformation while other ghost terms remain and are present in the minimal resolution of a general element of . 相似文献
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Mi Hee Park Byung Gyun Kang Phan Thanh Toan 《Journal of Pure and Applied Algebra》2018,222(8):2299-2309
Let be the power series ring over a commutative ring R with identity. For , let denote the content ideal of f, i.e., the ideal of R generated by the coefficients of f. We show that if R is a Prüfer domain and if such that is locally finitely generated (or equivalently locally principal), then a Dedekind–Mertens type formula holds for g, namely for all . More generally for a Prüfer domain R, we prove the content formula for all . As a consequence it is shown that an integral domain R is completely integrally closed if and only if for all nonzero , which is a beautiful result corresponding to the well-known fact that an integral domain R is integrally closed if and only if for all nonzero , where is the polynomial ring over R.For a ring R and , if is not locally finitely generated, then there may be no positive integer k such that for all . Assuming that the locally minimal number of generators of is , Epstein and Shapiro posed a question about the validation of the formula for all . We give a negative answer to this question and show that the finiteness of the locally minimal number of special generators of is in fact a more suitable assumption. More precisely we prove that if the locally minimal number of special generators of is , then for all . As a consequence we show that if is finitely generated (in particular if ), then there exists a nonnegative integer k such that for all . 相似文献
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Let D be a commutative domain with field of fractions K, let A be a torsion-free D-algebra, and let B be the extension of A to a K-algebra. The set of integer-valued polynomials on A is , and the intersection of with is , which is a commutative subring of . The set may or may not be a ring, but it always has the structure of a left -module.A D-algebra A which is free as a D-module and of finite rank is called -decomposable if a D-module basis for A is also an -module basis for ; in other words, if can be generated by and A. A classification of such algebras has been given when D is a Dedekind domain with finite residue rings. In the present article, we modify the definition of -decomposable so that it can be applied to D-algebras that are not necessarily free by defining A to be -decomposable when is isomorphic to . We then provide multiple characterizations of such algebras in the case where D is a discrete valuation ring or a Dedekind domain with finite residue rings. In particular, if D is the ring of integers of a number field K, we show that an -decomposable algebra A must be a maximal D-order in a separable K-algebra B, whose simple components have as center the same finite unramified Galois extension F of K and are unramified at each finite place of F. Finally, when both D and A are rings of integers in number fields, we prove that -decomposable algebras correspond to unramified Galois extensions of K. 相似文献
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Katsunori Kawamura 《Linear algebra and its applications》2012,436(7):2638-2652
Let denote the -algebra defined as the direct sum of all matrix algebras . It is known that has a non-cocommutative comultiplication . From a certain set of transformations of integers, we construct a universal R-matrix R of the -bialgebra such that the quasi-cocommutative -bialgebra is triangular. Furthermore, it is shown that certain linear Diophantine equations are corresponded to the Yang–Baxter equations of R. 相似文献
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Neil J.Y. Fan Peter L. Guo Grace L.D. Zhang 《Journal of Pure and Applied Algebra》2017,221(1):237-250
Parabolic R-polynomials were introduced by Deodhar as parabolic analogues of ordinary R-polynomials defined by Kazhdan and Lusztig. In this paper, we are concerned with the computation of parabolic R-polynomials for the symmetric group. Let be the symmetric group on , and let be the generating set of , where for , is the adjacent transposition. For a subset , let be the parabolic subgroup generated by J, and let be the set of minimal coset representatives for . For in the Bruhat order and , let denote the parabolic R-polynomial indexed by u and v. Brenti found a formula for when , and obtained an expression for when . In this paper, we provide a formula for , where and i appears after in v. It should be noted that the condition that i appears after in v is equivalent to that v is a permutation in . We also pose a conjecture for , where with and v is a permutation in . 相似文献
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Paolo Albano Piermarco Cannarsa Teresa Scarinci 《Journal of Differential Equations》2018,264(5):3312-3335
In a bounded domain of with boundary given by a smooth -dimensional manifold, we consider the homogeneous Dirichlet problem for the eikonal equation associated with a family of smooth vector fields subject to Hörmander's bracket generating condition. We investigate the regularity of the viscosity solution T of such problem. Due to the presence of characteristic boundary points, singular trajectories may occur. First, we characterize these trajectories as the closed set of all points at which the solution loses point-wise Lipschitz continuity. Then, we prove that the local Lipschitz continuity of T, the local semiconcavity of T, and the absence of singular trajectories are equivalent properties. Finally, we show that the last condition is satisfied whenever the characteristic set of is a symplectic manifold. We apply our results to several examples. 相似文献
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Radu Ignat Luc Nguyen Valeriy Slastikov Arghir Zarnescu 《Comptes Rendus Mathematique》2018,356(9):922-926
For , we consider the Ginzburg–Landau functional for -valued maps defined in the unit ball with the vortex boundary data x on . In dimensions , we prove that, for every , there exists a unique global minimizer of this problem; moreover, is symmetric and of the form for . 相似文献
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For every and every integer N, let be the minimum of the distance of τ from the sums , where . We prove that , for all sufficiently large positive integers N (depending on C and τ), where C is any positive constant less than . 相似文献
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A finite Borel measure μ in is called a frame-spectral measure if it admits an exponential frame (or Fourier frame) for . It has been conjectured that a frame-spectral measure must be translationally absolutely continuous, which is a criterion describing the local uniformity of a measure on its support. In this paper, we show that if any measures ν and λ without atoms whose supports form a packing pair, then is translationally singular and it does not admit any Fourier frame. In particular, we show that the sum of one-fourth and one-sixteenth Cantor measure does not admit any Fourier frame. We also interpolate the mixed-type frame-spectral measures studied by Lev and the measure we studied. In doing so, we demonstrate a discontinuity behavior: For any anticlockwise rotation mapping with , the two-dimensional measure , supported on the union of x-axis and , always admit a Fourier frame. Furthermore, we can find such that it forms a Fourier frame for with frame bounds independent of θ. Nonetheless, does not admit any Fourier frame. 相似文献
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Anuj Jakhar Sudesh K. Khanduja Neeraj Sangwan 《Journal of Pure and Applied Algebra》2018,222(4):889-899
Let v be a Krull valuation of a field with valuation ring . Let θ be a root of an irreducible trinomial belonging to . In this paper, we give necessary and sufficient conditions involving only for to be integrally closed. In the particular case when v is the p-adic valuation of the field of rational numbers, and , then it is shown that these conditions lead to the characterization of primes which divide the index of the subgroup in , where is the ring of algebraic integers of K. As an application, it is deduced that for any algebraic number field K and any quadratic field L not contained in K, we have if and only if the discriminants of K and L are coprime. 相似文献
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In a Dedekind domain D, every non-zero proper ideal A factors as a product of powers of distinct prime ideals . For a Dedekind domain D, the D-modules are uniserial. We extend this property studying suitable factorizations of a right ideal A of an arbitrary ring R as a product of proper right ideals with all the modules uniserial modules. When such factorizations exist, they are unique up to the order of the factors. Serial factorizations turn out to have connections with the theory of h-local Prüfer domains and that of semirigid commutative GCD domains. 相似文献
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Let R be an associative ring with unit and denote by the homotopy category of complexes of projective left R-modules. Neeman proved the theorem that is -compactly generated, with the category of left bounded complexes of finitely generated projective R-modules providing an essentially small class of such generators. Another proof of Neeman's theorem is explained, using recent ideas of Christensen and Holm, and Emmanouil. The strategy of the proof is to show that every complex in vanishes in the Bousfield localization . 相似文献