The finite basis problem for the semigroups of order-preserving mappings
A. S. Vernitskiǐ · Proceedings of the Royal Society of Edinburgh Section A Mathematics · 1999
Developing an approach of Repnitskii and Volkov, we focus on properties of semigroups of order-preserving mappings on finite chains; in particular, we show that the class of all these semigroups has no finite quasi-identity basis (although it has an infinite one).