设RW n是有限链[n]上的正则保序且压缩奇异变换半群。对任意的r(2≤r≤n-1),考虑半群W(n,r)={α∈RW n:|Imα|≤r}的非群元秩和非幂等元秩。证明了:W(n,r)是由秩为r的元素生成的;确定了当1≤l≤r时,半群W(n,r)关于其理想W(n,l)的相关秩。
Let RWn be the semigroup of all regular order-preserving and compressing singular transformations on a finite-chain [n].For an arbitrary integer r(2≤r≤n-1), the non-group rank and non-idempotent rank of the semig-roup W(n,r)={α∈RWn:|Imα|≤r} were studied.The semigroup W(n,r) generated by elements of rank r is proved.Furthermore, it is shown that for 1≤l≤r, the relative rank of the semigroup W( n,r) with respect to itself each ideal W( n,l) .