Definition:Limit Inferior

Let $$\left \langle {x_n} \right \rangle$$ be a bounded sequence in $\R$.

Let $$L$$ be the set of all real numbers which are the limit of some subsequence of $$\left \langle {x_n} \right \rangle$$.

From Existence of Maximum and Minimum of Bounded Sequence, $$L$$ has a minimum.

This minimum is called the limit inferior or just liminf.

It can be denoted $$\liminf_{l \to \infty} \left({x_n}\right) = \underline l$$.

Compare limit superior.