Greater than. The limit of a function at a from above is the limit of f(x) as x → a for values of x > a. It can be written as f(a⁺ ) or $\underset{x\searrow a}{\text{lim}}f\left(x\right)$. A function f(x) is continuous at a if and only if the limit from above and the limit from below exist and are equal.