ABSTRACT
LEAST UPPER BOUND AND GREATEST LOWER BOUND
In Chapters 21 and 22 the concepts of upper bounds and lower bounds were considered for the particular posets (El , <) where < is the usual "less than or equal to" relation. In Chapter 27, generalizations of these concepts were investigated for any set A and any partial order relation on A. Likewise, in Chapters 21 and 22 the notions of least upper bound and greatest lower bound were considered for the particular poset (E1 , <). These concepts are now generalized for any partially ordered set. As before, the symbol < is sometimes used for the partial order relation. But < is NOT necessarily the ordinary "less than or equal to." At times the actual partial order relation will be used, e.g., C in (Paa, b,
C).
