arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1106.6192math.RA
收藏

Morita context环之间的同构

Isomorphisms between Morita context rings

C. Boboc, S. Dascalescu, L. van Wyk

摘要:

令$(R, S,_R\negthinspace M_S,_S\negthinspace N_R, f, g)$是一般的森田上下文,并且令$T=[{cc} R &_RM_S_SN_R & S]$是与该上下文相关联的环。类似地,让$T'=[{cc} R' & M' N' & S']$成为另一个森田上下文环。研究了从$T$到$T'$的环同构的集合${Iso}(T,T')$.我们对这个问题的兴趣是出于:(i)确定环$T$的自同构群的问题,以及(ii)这类广义矩阵环的非对角瓦片问题的恢复。本文引入了两类从$T$到$T'$的同构,它们的不交并记为${Iso}_0(T,T')$ .我们用$T$和$T'$的$\Z$ -分级环结构描述了${Iso}_0(T,T')$.我们的主要结果刻画了${Iso}_0(T,T')$是由从$T$到$T'$的所有半分次同构和所有反半分次同构组成的集合,条件是环$R'$和$S'$是不可分解的,并且$M'$和$N'$中至少有一个是非零的;特别地,${Iso}_0(T,T')$包含从$T$到$T'$的所有分次同构和所有反分次同构.我们还提出了一种情况,其中${Iso}_0(T,T')={Iso}(T,T')$。这是在$R,S,R'$和$S'$是仅具有平凡幂等元的环并且所有森田映射为零的情况下。特别地,这表明$T$的自同构群是完全确定的。

英文摘要:

Let $(R, S,_R\negthinspace M_S,_S\negthinspace N_R, f, g)$ be a general Morita context, and let $T=[{cc} R &_RM_S_SN_R & S]$ be the ring associated with this context. Similarly, let $T'=[{cc} R' & M' N' & S']$ be another Morita context ring. We study the set ${Iso}(T,T')$ of ring isomorphisms from $T$ to $T'$. Our interest in this problem is motivated by: (i) the problem to determine the automorphism group of the ring $T$, and (ii) the recovery of the non-diagonal tiles problem for this type of generalized matrix rings. We introduce two classes of isomorphisms from $T$ to $T'$, the disjoint union of which is denoted by ${Iso}_0(T,T')$. We describe ${Iso}_0(T,T')$ by using the $\Z$-graded ring structure of $T$ and $T'$. Our main result characterizes ${Iso}_0(T,T')$ as the set consisting of all semigraded isomorphisms and all anti-semigraded isomorphisms from $T$ to $T'$, provided that the rings $R'$ and $S'$ are indecomposable and at least one of $M'$ and $N'$ is nonzero; in particular ${Iso}_0(T,T')$ contains all graded isomorphisms and all anti-graded isomorphisms from $T$ to $T'$. We also present a situation where ${Iso}_0(T,T')={Iso}(T,T')$. This is in the case where $R,S,R'$ and $S'$ are rings having only trivial idempotents and all the Morita maps are zero. In particular, this shows that the group of automorphisms of $T$ is completely determined.

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。

↑