On free group algebras in division rings with uncountable center

Let be a division algebra with uncountable center . If contains a noncommutative free -algebra, then also contains the -group algebra of the free group of rank 2.

     

Nonabelian free subgroups in homomorphic images of valued quaternion division algebras

Given a quaternion division algebra a noncentral element is called pure if its square belongs to the center. A theorem of Rowen and Segev (2004) asserts that for any quaternion division algebra of positive characteristic and any pure element the quotient of by the normal subgroup generated by is abelian-by-nilpotent-by-abelian. In this note we construct a quaternion division algebra of characteristic zero containing a pure element such that contains a nonabelian free group. This demonstrates that the situation in characteristic zero is very different.

     

Normal subgroups ofSL 1,D and the classification of finite simple groups

LetD be a division algebra of degree three over an algebraic number fieldK and let G = SL_D. We prove that the normal subgroup structure of G(K) is given by the Platonov-Margulis conjecture. The proof uses the classification of finite simple groups.     

On Homomorphism of Valuation Algebras

In this paper, firstly, a necessary condition and a sufficient condition for an isomorphism between two semiring-induced valuation algebras to exist are presented respectively. Then a general valuation homomorphism based on different domains is defined, and the corresponding homomorphism theorem of valuation algebra is proved.     

Non-noetherian regular rings of dimension 2

We study connected, not necessarily noetherian, regular rings of global dimension 2.

     

Actions of Solvable Algebraic Groups on Central Simple Algebras

Let k be an algebraically closed base field of arbitrary characteristic. In this paper, we study actions of a connected solvable linear algebraic group G on a central simple algebra Q. The main result is the following: Q can be split G-equivariantly by a finite-dimensional splitting field, provided that G acts “algebraically,” i.e., provided that Q contains a G-stable order on which the action is rational. As an application, it is shown that rational torus actions on prime PI-algebras are induced by actions on commutative domains. Presented by Paul Smith.     

Division algebras over -fields

Using elementary methods we prove a theorem of Rost, Serre, and Tignol that any division algebra of degree 4 over a -field containing is cyclic. Our methods also show any division algebra of degree 8 over a -field containing is cyclic.

     

约束半环诱导的赋值代数的轮廓解及其算法

本文研究了约束半环所诱导的赋值代数的轮廓解及其算法的问题.利用约束半环的性质,以及基于记忆约束半环赋值的方法,获得了约束半环所诱导的赋值代数的轮廓解的概念,性质以及算法的相关结论,推广了文献[2]关于全序幂等半环诱导的赋值代数的轮廓解的结果.     

Finite quotients of the multiplicative group of a finite dimensional division algebra are solvable

We prove that finite quotients of the multiplicative group of a finite dimensional division algebra are solvable. Let be a finite dimensional division algebra having center , and let be a normal subgroup of finite index. Suppose is not solvable. Then we may assume that is a minimal nonsolvable group (MNS group for short), i.e. a nonsolvable group all of whose proper quotients are solvable. Our proof now has two main ingredients. One ingredient is to show that the commuting graph of a finite MNS group satisfies a certain property which we denote Property . This property includes the requirement that the diameter of the commuting graph should be , but is, in fact, stronger. Another ingredient is to show that if the commuting graph of has Property , then is open with respect to a nontrivial height one valuation of (assuming without loss of generality, as we may, that is finitely generated). After establishing the openness of (when is an MNS group) we apply the Nonexistence Theorem whose proof uses induction on the transcendence degree of over its prime subfield to eliminate as a possible quotient of , thereby obtaining a contradiction and proving our main result.

     

Exponential growth of Lie algebras of finite global dimension

Let be a connected finite type graded Lie algebra. If dim and gldim , then log index . If, moreover, , then for some ,    dim where log index as

     

代数闭域上三维非交换代数的分类

研究了代数闭域K上三维非交换代数的分类.在已有三维交换代数分类的基础上,获得了代数闭域K上三维非交换代数A的分类,共有十二种类型.并且给出了非交换代数对应的路代数以及它们之间的一些关系.     

Wedderburn's factorization theorem application to reduced -theory

This article provides a short and elementary proof of the key theorem of reduced -theory, namely Platonov's Congruence theorem. Our proof is based on Wedderburn's factorization theorem.

     

Four-Dimensional Real Third-Power Associative Division Algebras

We study third-power associative division algebras A over a field 𝕂 of characteristic different from 2. Those algebras having dimension ≤2 are commutative. When 𝕂 is the field ? of real numbers, those algebras having dimension 4 are power-commutative in each of the following two cases:

1. A contains a central element;

2. A satisfies the additional identity (x, x³, x) = 0.

     

Hopf代数的冲积的弱整体维数

设H是有限维Hopf代数,A是交换的H-模代数。当H~*是幺模且A中存在迹为1的元素时,本文证明冲积A#H与代数A的弱整体维数相等。