quality:correction, structural:scholar_edition
Minimum and maximum value of a function

Consider the following notation:

This denotes the minimum value of the objective function x + 1, when choosing x from the set of real numbers R {\displaystyle \mathbb {R} }. The minimum value in this case is 1, occurring at x = 0.

Similarly, the notation

asks for the maximum value of the objective function 2 x, where x may be any real number. In this case, there is no such maximum as the objective function is unbounded, so the answer is " infinity " or " undefined ".