Unimodularity

linear-algebra

Definition

Unimodularity

A matrix $U\in {\mathbb{Z}}^{n\times n}$ is unimodular if

$$\det (U)=\pm 1.$$

Equivalently, $U$ is invertible over $\mathbb{Z}$ — both $U$ and $U^{-1}$ have integer entries.