Maximal Non-Trivial Border (String)

Definition

Maximal Non-Trivial Border (String)

The maximal non-trivial border of a string $S$ is its longest non-trivial border: the longest string $X$ that is both a prefix and a suffix of $S$ and satisfies $0<|X|<|S|$. If no such string exists, $S$ has no maximal non-trivial border.