Real Brauer characters

In this paper, we determine the structure of finite groups with a small number of real-valued irreducible Brauer characters.     

Linked Primes and Orders in Artinian Rings

It is shown that prime ideals of a Noetherian ring are linked if and only if certain corresponding prime ideals are linked in an associated Artinian ring. Furthermore, it is shown that there is a canonical linking ideal, which can be found by using a construction based on middle annihilator ideals.     

The Local Structure of Graded Representations

In this article we show that the local structure of the projective representation space of a graded algebra can locally be described by quivers with an automorphism of their path algebra, a weighted twist. We describe the quotient spaces of these weighted twisted quiver settings and determine which of them are smooth.     

Multivariate interpolation in odd-dimensional euclidean spaces using multiquadrics

Let or . Givenf: ⁿ , we establish convergence orders of interpolation where the cardinal functionx withx(j)=_0j is a linear combination of integer shifts, of a fast decaying function

Noncommutative cyclic covers and maximal orders on surfaces

In this paper, we construct various examples of maximal orders on surfaces, including some del Pezzo orders, some ruled orders and some numerically Calabi-Yau orders. The method of construction is a noncommutative version of the cyclic covering trick. These noncommutative cyclic covers are very computable and we give a formula for their ramification data. This often allows us to determine if a maximal order, described via ramification data, can be constructed as a noncommutative cyclic cover. The construction also has applications to Brauer-Severi varieties and, in the quaternion case, we show how to obtain some Brauer-Severi varieties from G-Hilbert schemes of P¹-bundles.     

算子和右端都近似给定的第一类算子方程的广义Arcangeli方法

本文利用正则化方法解算子和右端都是近似给定的第一类算子方程,利用广义Arcangeli准则决定正则参数,给出正则解的收敛性和渐近收敛阶估计,以及算子为Fredholm积分算子时的正则解的一致收敛性。     

Characterization of Groups L2(q) by NSE Where q∈{17, 27, 29}

The authors show that linear simple groups L_2(q) with q ∈ {17, 27, 29} can be uniquely determined by nse(L_2(q)), which is the set of numbers of elements with the same order.     

Higher Algebraic <Emphasis Type="BoldItalic">K</Emphasis>-theory for Twisted Laurent Series Rings Over Orders and Semisimple Algebras

Let R be the ring of integers in a number field F, Λ any R-order in a semisimple F-algebra Σ, α an R-automorphism of Λ. Denote the extension of α to Σ also by α. Let Λ _α [T] (resp. Σ _α [T] be the α-twisted Laurent series ring over Λ (resp. Σ). In this paper we prove that (i) There exist isomorphisms ) for all n ≥ 1. (ii) is an l-complete profinite Abelian group for all n≥2. (iii)for all n≥2. (iv)is injective with uniquely l-divisible cokernel (for all n≥2). (v) K _–1(Λ), K _–1(Λ _α [T]) are finitely generated Abelian groups. Presented by Alain Verschoren.     

Global construction of associated orders in complex multiplication

Let E/L be an elliptic curve defined over a number field L with complex multiplication by the ring of integers of a quadratic imaginary number field K⊆L. We fix a prime ideal p in K and assume E to have good reduction modulo p. We consider cosets of the form P+G_m, where G_m denotes the group of points of order p^m and P a point of order p^r+m, , which can be viewed as the set of all “p^m-th roots” of some point in G_r.In analogy to the Kummer theory such a coset gives rise to the definition of an order in an algebra M_P and to an associated order A defined below by its local components. These objects naturally come into play in the Galois module structure of rings of integers in ray class fields over K. It is the aim of this article to construct global generators both for and A as algebras over the ring of integers of L. For the convenience of the reader we also include from (J. Number Theory 77 (1999) 97) a simple construction of Galois generators for over A. We thereby show that these generators also fit in the setting of this article that is more general than in [Sch4]. The main results in Theorems 3, 6 and 7 are obtained assuming the base field L to contain “enough” torsion points of E.     

Optimal selection from distributions with unknown parameters: Robustness of Bayesian models

We consider the problem of making one choice from a known number of i.i.d. alternatives. It is assumed that the distribution of the alternatives has some unknown parameter. We follow a Bayesian approach to maximize the discounted expected value of the chosen alternative minus the costs for the observations. For the case of gamma and normal distribution we investigate the sensitivity of the solution with respect to the prior distributions. Our main objective is to derive monotonicity and continuity results for the dependence on parameters of the prior distributions. Thus we prove some sort of Bayesian robustness of the model.