Remark on quasi-ideals of ordered semigroups
  The aim is to correct part of the Remark 3 of my paper "On regular, intra-regular ordered semigroups" in Pure Math. Appl. (PU.M.A.) 4, no. 4 (1993), 447--461. On this occasion, some further results and the similarity between the $po$-semigroups and the $le$-semigroups is discussed. 
Niovi Kehayopulu
math.GM