“…It is well known that x * is (α 1 φ 1 , · · · , α 6 φ 6 , c 1 φ 7 , c 2 φ 8 )-optimal if and only if x * is (α 1 φ 1 , · · · , α 6 φ 6 )-feasible (feasibility) and (4) (optimality) should be satisfied with the given forall-exists quantifiers. For efficient methods of checking feasibility of various linear interval systems, we refer the readers to [5,10,11,[16][17][18][19][20][21]. In the last section, we analyse two different types of feasible solutions with mixed constraints, which have not yet been studied, and obtain the full characterization of such special cases of UO-optimality.…”