On linearly ordered index sets for ordinal sums in the sense of A. H. Clifford yielding uninorms

This paper focuses on the topic of ordinal sums of semigroups in the sense of A. H. Clifford - a method for constructing a new semigroup from a given system of semigroups indexed by a linearly ordered index set. We completely describe the linearly ordered index set for an ordinal sum of semigroups yielding a uninorm.