https://en.wikipedia.org/wiki/Upper_and_lower_bounds
WebExamples. For example, 5 is a lower bound for the set S = {5, 8, 42, 34, 13934} (as a subset of the integers or of the real numbers, etc.), and so is 4.On the other hand, 6 is not a lower bound for S since it is not smaller than every element in S. The set S = {42} has 42 as both an upper bound and a lower bound; all other numbers are either an upper bound or a …