Definition: n-Periodical Complex Sequence

A complex sequence $(a_k)_{k\in\mathbb Z}$ is called $n$-periodical, if there is a positive integer $n\in\mathbb Z$ such that $a_k=a_l$ for all $k(n)\equiv l(n)$, i.e. for all integers $k,l\in\mathbb Z$ being congruent modulo $n.$

Chapters: 1
Lemmas: 2

Thank you to the contributors under CC BY-SA 4.0!