For a ring R(not necessarily commutative)with identity,the comaximal graph of R,denoted byΩ(R),is a graph whose vertices are all the nonunit elements of R,and two distinct vertices a and b are adjacent if and only if...For a ring R(not necessarily commutative)with identity,the comaximal graph of R,denoted byΩ(R),is a graph whose vertices are all the nonunit elements of R,and two distinct vertices a and b are adjacent if and only if Ra+Rb=R.In this paper we consider a subgraphΩ_(1)(R)ofΩ(R)induced by R\Uℓ(R),where Uℓ(R)is the set of all left-invertible elements of R.We characterize those rings R for whichΩ_(1)(R)\J(R)is a complete graph or a star graph,where J(R)is the Jacobson radical of R.We investigate the clique number and the chromatic number of the graphΩ_(1)(R)\J(R),and we prove that if every left ideal of R is symmetric,then this graph is connected and its diameter is at most 3.Moreover,we completely characterize the diameter ofΩ_(1)(R)\J(R).We also investigate the properties of R whenΩ_(1)(R)is a split graph.展开更多
An embedding from a group algebra to a matrix algebra is given in this paper. By using it, a criterion for an invertible element in a group algebra is proven.
For a prime p,let E_（p,p^m）={（a p^（m-1） b d）｜a,b,c∈Z_p,d∈Z_（p^m）}. We first establish a ring isomorphism from Z_（p,p^m） onto E_（p,p^m）. Then we provide a way to compute-d and d^（-1） by using arithmeti...For a prime p,let E_（p,p^m）={（a p^（m-1） b d）｜a,b,c∈Z_p,d∈Z_（p^m）}. We first establish a ring isomorphism from Z_（p,p^m） onto E_（p,p^m）. Then we provide a way to compute-d and d^（-1） by using arithmetic in Z_p and Z_（p^m）, and characterize the invertible elements of E_（p,p^m）. Moreover, we introduce the minimal polynomial for each element in E_（p,p^m） and give its applications.展开更多
基金This research was supported by NSFC(12071484,11871479)Hunan Provincial Natural Science Foundation(2020JJ4675,2018JJ2479)the Research Fund of Beijing Information Science and Technology University(2025030).
文摘For a ring R(not necessarily commutative)with identity,the comaximal graph of R,denoted byΩ(R),is a graph whose vertices are all the nonunit elements of R,and two distinct vertices a and b are adjacent if and only if Ra+Rb=R.In this paper we consider a subgraphΩ_(1)(R)ofΩ(R)induced by R\Uℓ(R),where Uℓ(R)is the set of all left-invertible elements of R.We characterize those rings R for whichΩ_(1)(R)\J(R)is a complete graph or a star graph,where J(R)is the Jacobson radical of R.We investigate the clique number and the chromatic number of the graphΩ_(1)(R)\J(R),and we prove that if every left ideal of R is symmetric,then this graph is connected and its diameter is at most 3.Moreover,we completely characterize the diameter ofΩ_(1)(R)\J(R).We also investigate the properties of R whenΩ_(1)(R)is a split graph.
文摘An embedding from a group algebra to a matrix algebra is given in this paper. By using it, a criterion for an invertible element in a group algebra is proven.
基金Supported by the Research Project of Hubei Polytechnic University(17xjz03A)
文摘For a prime p,let E_（p,p^m）={（a p^（m-1） b d）｜a,b,c∈Z_p,d∈Z_（p^m）}. We first establish a ring isomorphism from Z_（p,p^m） onto E_（p,p^m）. Then we provide a way to compute-d and d^（-1） by using arithmetic in Z_p and Z_（p^m）, and characterize the invertible elements of E_（p,p^m）. Moreover, we introduce the minimal polynomial for each element in E_（p,p^m） and give its applications.
