Abstract
In this paper, some properties of the (k,k)-lower part of (is an element of,is an element of(k,qk))-fuzzy quasi-ideals are obtained. Then, we characterize regular ordered semigroups in terms of its (is an element of, is an element of(k,qk))-fuzzy quasi-ideals, (is an element of,is an element of(k,qk))-fuzzy generalized bi-ideals, (is an element of,is an element of (k,qk))-fuzzy left ideals and (is an element of,is an element of (k,qk))-fuzzy right ideals, and an equivalent condition for (is an element of,is an element of(k,qk))-fuzzy left (resp. right) ideals is obtained. Finally, the existence theorems for an (is an element of,is an element of(k,qk))-fuzzy quasi-ideal as well as for the minimality of an (is an element of,is an element of(k,qk))-fuzzy quasi-ideal of an ordered semigroup are provided.