Question

how to identify bound above or bound below set ?

Answer 1

An upper bound of a subset S of some partially ordered set (K, ≤) is an element of K which is greater than or equal to every element of S.The term lower bound is defined dually as an element of K which is less than or equal to every element of S. A set with an upper bound is said to be bounded from above by that bound, a set with a lower bound is said to be bounded from below by that bound.