共查询到20条相似文献,搜索用时 31 毫秒
1.
Artem N. Shevlyakov 《代数通讯》2017,45(9):3757-3767
A semigroup S is called an equational domain if any finite union of algebraic sets over S is algebraic. We give some necessary and su?cient conditions for a completely simple semigroup to be an equational domain. 相似文献
2.
We show that almost split sequences in the category of comodules over a coalgebraΓ with finite-dimensional right-hand term are direct limits of almost split sequences over finite dimensional subcoalgebras.
In previous work we showed that such almost split sequences exist if the right hand term has a quasifinitely copresented linear
dual. Conversely, taking limits of almost split sequences over finte-dimensional comodule categories, we then show that, for
countable-dimensional coalgebras, certain exact sequences exist which satisfy a condition weaker than being almost split,
which we call “finitely almost split”. Under additional assumptions, these sequences are shown to be almost split in the appropriate
category.
Sunto Dimostriamo che le successioni che quasi spezzano nella categoria dei comoduli su una coalgebra Γ con termine di destra di dimensione finita sono limiti diretti di successioni che quasi spezzano su sottoalgebre di dimensione finita. In un lavoro precedente abbiamo dimostrato che tali successioni che quasi spezzano esistono se il termine di destra ha un duale lineare quasi-finitamente copresentato. Viceversa, prendendo il limite delle successioni che quasi spezzano su categorie di comoduli di dimensione finita, dimostriamo che, per coalgebre di dimensione numerabile, esistono alcune successioni esatte che soddisfano una condizione più debole di essere quasi spezzanti, che noi chiamiamo “finitamente quasi spezzanti”. Sotto ipotesi aggiuntive, si dimostra che queste successioni quasi spezzano nelle opportune categorie.相似文献
3.
The inequalities su At su Am ≥ su Ap su Aq and At+ su Am≥ su Ap+ su Aq are studied and generalized. Here su A denotes the sum of elements of the square matrix A. 相似文献
4.
The inequality 3su A3 ⩾ su A su A2, which is known to hold for any symmetric nonnegative 3 X 3 matrix A, is sharpened in three different ways. Here su denotes the sum of elements. 相似文献
5.
In this article, we study the convergence of the inverse shearlet transform in arbitrary space dimensions. For every pair of admissible shearlets, we show that although the integral involved in the inversion formula from the continuous shearlet transform is convergent in the L2 sense, it is not true in general whenever pointwise convergence is considered. We give some su?cient conditions for the pointwise convergence to hold. Moreover, for any pair of admissible shearlets we show that the Riemannian sums defined by the inverse shearlet transform are convergent to the original function as the sampling density tends to infinity. 相似文献
6.
In this paper we show the existence of a solution, on any time intervals, in suitable Sobolev spaces for the 2D compressible
Euler equation in the exterior domain, when the Mach number is sufficiently small. We shall extend results obtained in [8]
in the case of an infinity velocity different from zero.
Sunto In questo lavoro proviamo l'esistenza di una soluzione, su ogni intervallo temporale, in opportuni spazi di Sobolev per le equazioni di Eulero 2D comprimibili in un dominio esterno, quando il numero di Mach è sufficientemente piccolo. Estenderemo i risultati ottenuti in [8] al caso di velocità all'infinito diversa da zero.相似文献
7.
The “No Gap Conjecture” of Brüstle–Dupont–Pérotin states that the set of lengths of maximal green sequences for hereditary algebras over an algebraically closed field has no gaps. This follows from a stronger conjecture that any two maximal green sequences can be “polygonally deformed” into each other. We prove this stronger conjecture for all tame hereditary algebras over any field, equivalently, for any acyclic tame skew-symmetrizable exchange matrix. 相似文献
8.
Francesco Altomare 《Rendiconti del Circolo Matematico di Palermo》1987,36(2):167-181
Si stabiliscono dei risultati concernenti la convergenza di reti di forme lineari positive verso una prefissata forma lineare positiva nel contesto di spazi di funzioni continue ed affini definite su un insieme convesso compatto. Si presentano degli esempi e delle applicazioni in spazi di funzioni continue, inC *-algebre di operatori su spazi di Hilbert e in spazi di Banach reticolati. 相似文献
9.
Using realizations of the positive discrete series representations of the Lie algebra su(1,1) in terms of Meixner—Pollaczek polynomials, the action of su(1,1) on Poisson kernels of these polynomials is considered. In the tensor product of two such representations, two sets of eigenfunctions
of a certain operator can be considered and they are shown to be related through continuous Hahn polynomials. As a result,
a bilinear generating function for continuous Hahn polynomials is obtained involving the Poisson kernel of Meixner—Pollaczek
polynomials; this result is also known as the Burchnall—Chaundy formula. For the positive discrete series representations
of the quantized universal enveloping algebra U
q
(su(1,1)) a similar analysis is performed and leads to a bilinear generating function for Askey—Wilson polynomials involving the Poisson
kernel of Al-Salam and Chihara polynomials.
July 6, 1997. Date accepted: September 23, 1998. 相似文献
10.
Allan Berele 《代数通讯》2013,41(11):4179-4182
Abstract Bounds are given for the diameter of commuting involution graphs of special linear groups over fields of characteristic 2. For 2- and 3-dimensional special linear groups over any finite field the disc sizes are determined. Examples are given of commuting involution graphs which have unbounded diameter. 相似文献
11.
Hisako Furuya 《Journal of Number Theory》1977,9(1):4-15
This paper has the following contents. 1°. In an abelian extension field K over the rational number field, any ambiguous ideal is a principal ideal in the genus field in the wide sense. 2°. A number theoretical proof of the following. In a cyclic extension field K over the rational number field, any ambiguous class ideal is a principal ideal in the genus field in the wide sense. 相似文献
12.
Brendan Creutz 《Journal of Number Theory》2011,131(11):2162-2174
We show that the p-torsion in the Tate-Shafarevich group of any principally polarized abelian variety over a number field is unbounded as one ranges over extensions of degree O(p), the implied constant depending only on the dimension of the abelian variety. 相似文献
13.
In this paper, we apply Moriwaki's arithmetic height functionsto obtain an analogue of Silverman's specialization theoremfor families of Abelian varieties over K, where K is any fieldfinitely generated over Q. 2000 Mathematics Subject Classification11G40, 14K15. 相似文献
14.
We present a simple combinatorial rule to expand the plethysm Pn[S(1a,b)](x) of a power summetric function Pn(x) and a Schur function of hook shapeS(1a,b)(x), as a sum of Schur functions. The key ingredient of our proof is a correspondence between the circle diagrams, introduced by Chen, Garsia and Remmel [6] in their SXP algorithm to compute the Schur function expansion of Pn[Sλ], and certain special rim hook and transposed special rim hook tabloids which is of interest in its own right. As an application of our rule, we drive explicit formulas for the coefficient of any Schur function of hook shape in the Schur function expansion of a plethysm of any two Schur functions of hook shape. 相似文献
15.
We prove analogues of Grauert–Mülich and Flenner?s restriction theorems for semistable principal Higgs bundle over any smooth complex projective variety. 相似文献
16.
17.
Ehud Meir 《Algebras and Representation Theory》2012,15(2):391-405
We define a notion of complexity for modules over group rings of infinite groups. This generalizes the notion of complexity
for modules over group algebras of finite groups. We show that if M is a module over the group ring kG, where k is any ring and G is any group, and M has f-complexity (where f is some complexity function) over some set of finite index subgroups of G, then M has f-complexity over G (up to a direct summand). This generalizes the Alperin-Evens Theorem, which states that if the group G is finite then the complexity of M over G is the maximal complexity of M over an elementary abelian subgroup of G. We also show how we can use this generalization in order to construct projective resolutions for the integral special linear
groups, SL(n, ℤ), where n ≥ 2. 相似文献
18.
A. G. Vladimirov 《Mathematical Notes》2018,103(3-4):378-394
The Zermelo–Fraenkel set theory with the underlying intuitionistic logic (for brevity, we refer to it as the intuitionistic Zermelo–Fraenkel set theory) in a two-sorted language (where the sort 0 is assigned to numbers and the sort 1, to sets) with the collection scheme used as the replacement scheme of axioms (the ZFI2C theory) is considered. Some partial conservativeness properties of the intuitionistic Zermelo–Fraenkel set theory with the principle of double complement of sets (DCS) with respect to a certain class of arithmetic formulas (the class all so-called AEN formulas) are proved. Namely, let T be one of the theories ZFI2C and ZFI2C + DCS. Then (1) the theory T+ECT is conservative over T with respect to the class of AEN formulas; (2) the theory T+ECT+M is conservative over T+M{su?} with respect to the class of AEN formulas. Here ECT stands for the extended Church’s thesis, Mis the strong Markov principle, and M{su?} is the weak Markov principle. The following partial conservativeness properties are also proved: (3) T+ECT+M is conservative over T with respect to the class of negative arithmetic formulas; (4) the classical theory ZF2 is conservative over ZFI2C with respect to the class of negative arithmetic formulas. 相似文献
19.
In this paper, we propose a robust sequential quadratic programming (SQP) method for nonlinear programming without using any explicit penalty function and filter. The method embeds the modified QP subproblem proposed by Burke and Han (Math Program 43:277–303, 1989) for the search direction, which overcomes the common difficulty in the traditional SQP methods, namely the inconsistency of the quadratic programming subproblems. A non-monotonic technique is employed further in a framework in which the trial point is accepted whenever there is a sufficient relaxed reduction of the objective function or the constraint violation function. A forcing sequence possibly tending to zero is introduced to control the constraint violation dynamically, which is able to prevent the constraint violation from over-relaxing and plays a crucial role in global convergence and the local fast convergence as well. We prove that the method converges globally without the Mangasarian–Fromovitz constraint qualification (MFCQ). In particular, we show that any feasible limit point that satisfies the relaxed constant positive linear dependence constraint qualification is also a Karush–Kuhn–Tucker point. Under the strict MFCQ and the second order sufficient condition, furthermore, we establish the superlinear convergence. Preliminary numerical results show the efficiency of our method. 相似文献
20.
Linchao Hu Moxun Tang Zhongdao Wu Zhiyong Xi Jianshe Yu 《Journal of Differential Equations》2019,266(7):4377-4393
Dengue fever and Zika are mosquito-borne diseases threatening human health. A novel strategy for mosquito-borne disease control uses the bacterium Wolbachia to block virus transmission. It requires releasing Wolbachia infected mosquitoes to exceed a threshold level. Since an accurate forecast for temperature and rainfall, the major environmental conditions regulating the mosquito dynamics, is often not available over a long time period, it is important to explore how the threshold releasing level changes in random environments. In this work, we estimate the threshold level in a stochastic system of differential equations where the reproduction rates of mosquitoes change randomly. We prove that the threshold level is, surprisingly, defined by a deterministic curve that does not fluctuate with environmental conditions. The major difficulty in the proof is to construct various auxiliary curves to limit the dynamic behaviors of the whole family of innumerable solutions satisfying a given initial condition. 相似文献