Xu, Bo; Feng, Rongquan Locally maximal idempotent-generated subsemigroups of \(PO_n\). (Chinese. English summary) Zbl 1274.20079 Math. Pract. Theory 42, No. 4, 200-203 (2012). Summary: The semigroup \(PO_n\) of all singular partial order-preserving transformations on a finite chain is studied. By analyzing the idempotent elements, the structure and the classification of the locally maximal idempotent-generated subsemigroups of \(PO_n\) are obtained. MSC: 20M20 Semigroups of transformations, relations, partitions, etc. 20M05 Free semigroups, generators and relations, word problems Keywords:order-preserving transformation semigroups; idempotents; maximal subsemigroups; idempotent-generated subsemigroups PDFBibTeX XMLCite \textit{B. Xu} and \textit{R. Feng}, Math. Pract. Theory 42, No. 4, 200--203 (2012; Zbl 1274.20079)