Definition
If is an upper bound of a subset , and , we call the (unique) maximum of .
Upper Bound
For a subset , if is a real number such that for all elements , , we say that is an upper bound of .
If M is an upper bound of a subset S⊂R, and M∈S, we call M the (unique) maximum of S.
For a subset S⊂R, if a is a real number such that for all elements x∈S, x≤a, we say that a is an upper bound of S.