arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0903.3820math.RTmath.RA
收藏

Jordan簇的不可约分支

Irreducible components of the Jordan varieties

N. Iyudu

摘要:

我们宣布在这里的一些结果有关表示论的代数$R=k<x,y>/ (xy-yx-y^2)$,被称为约旦平面(或约旦代数)。本文研究了Jordan代数上有限维模的分类问题。对于任意维数$n$,给出了表示簇$mod (R,n)$(我们称之为Jordan簇)的不可约分支的完整描述.它是在与$Y$的Jordan标准形相关的这个变种的分层的基础上获得的。表示簇的任何不可约分量只包含一个与$n$的某个划分相关的层,并且是该层的闭包。因此,不可约分量的数目等于$n$的划分数目。作为上述结果的预备,我们给出了Jordan代数上两两非同构不可约模$S_{a}$的完备集,以及它们如何粘到不可约模上的规则.也就是说,我们表明,${\rm Ext}^1(S_{a},S_{b})=0$,如果$a \neq b $。研究了自同态环上的象代数的性质。特别是,来自最重要层的表示图像,对应于完整的Jordan块$Y$。这层原来是唯一的积木模拟的Krull-Remark-Schmidt分解定理的水平上的不可约组件。沿着这条线,我们建立了一个类似的Gerstenhaber-Taussky-Motzkin定理的维数代数产生的两个交换矩阵。另一个事实是关于这些象代数的驯服-野性问题。证明了$n$维表示的象代数对$n \leq 4$是驯服的,对$n \geq 5$是狂野的.

英文摘要:

We announce here a number of results concerning representation theory of the algebra $R=k<x,y>/ (xy-yx-y^2)$, known as Jordan plane (or Jordan algebra). We consider the question on 'classification' of finite-dimensional modules over the Jordan algebra. Complete description of irreducible components of the representation variety $mod (R,n)$, which we call a Jordan variety' is given for any dimension $n$. It is obtained on the basis of the stratification of this variety related to the Jordan normal form of $Y$. Any irreducible component of the representation variety contains only one stratum related to a certain partition of $n$ and is the closure of this stratum. The number of irreducible components therefore is equal to the number of partitions of $n$. As a preparation for the above result we describe the complete set of pairwise non-isomorphic irreducible modules $S_{a}$ over the Jordan algebra, and the rule how they could be glued to indecomposables. Namely, we show that ${\rm Ext}^1(S_{a},S_{b})=0$, if $a \neq b $. We study then properties of the image algebras in the endomorphism ring. Particularly, images of representations from the most important stratum, corresponding to the full Jordan block $Y$. This stratum turns out to be the only building block for the analogue of the Krull-Remark-Schmidt decomposition theorem on the level of irreducible components. Along this line we establish an analogue of the Gerstenhaber--Taussky--Motzkin theorem on the dimension of algebras generated by two commuting matrices. Another fact concerns with the tame-wild question for those image algebras. We show that all image algebras of $n$-dimensional representations are tame for $n \leq 4$ and wild for $n \geq 5$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑