{"DOI":"10.2478/s12175-014-0279-6","abstract":"AbstractAn ordered monoid S in which every principal left ideal, regarded as an S-poset, is projective is called an ordered left PP monoid, for short, an ordered lpp monoid. In this paper, we introduce a new kind of ordered relations instead of Green relations adopted by J. B. Fountain, ordered lpp monoids are described by these ordered relations. Some similar results of c-rpp semigroups are duduced and proved, in particular, Fountain's results about C-lpp monoids are generalized to ordered monoids.","author":[{"family":"Shi"}],"id":"unknown","issued":{"date-parts":[[2014,1,1]]},"publisher":"Walter de Gruyter GmbH","title":"Ordered left PP monoids","type":"article-journal","volume":"64"}