\begin{definition}[Definition:Basic Null Sequence]
The sequences defined as:
:$\sequence {\dfrac 1 {n^r} }_{n \mathop \in \N}$ for $r \in \R: r > 0$
:$\sequence {\alpha^n}_{n \mathop \in \N}$ for $\alpha \in \C: \cmod {\alpha} < 1$
are known as the '''basic null sequences'''.
\end{definition}