一类变换半群的正则元

在等价关系E F的假设下,给出了变换半群TFE（X）的正则元的性质.利用这些性质,简化了正则元的格林关系,得到了更为简单的描述.     

一类线性变换半群的格林关系

Let V be a linear space over a field F with finite dimension, L（V） the semigroup, under composition, of all linear transformations from V into itself. Suppose that V = V1 V2 ... Vm is a direct sum decomposition of V, where V1,V2,..., Vm are subspaces of V with the same dimension. A linear transformation f ∈ L（V） is said to be sum-preserving, if for each i （1 ≤ i ≤ m）, there exists some j （1 ≤ j ≤ m） such that f（Vi） Vj. It is easy to verify that all sum-preserving linear transformations form a subsemigroup of L（V） which is denoted by L （V）. In this paper, we first describe Green＇s relations on the semigroup L （V）. Then we consider the regularity of elements and give a condition for an element in L （V） to be regular. Finally, Green＇s equivalences for regular elements are also characterized.     

规则连接的n级三角梯形电阻网络的精简研究

利用Y→△电导等效转换公式,将各边电阻皆相等的n级三角梯形电阻网络简化为1级三角形电阻网络,其腰边电-Pn-1(m-α)阻为nr,底边电阻递推通式为Rn=Qn-1(m-β)-Pn-1(m-α)/αQn-1(m-β)-βPn-1(m-α).