Unimodular Matrix

A Matrix with Integer elements and Determinant det ± 1, also called a Unit Matrix.

The inverse of a unimodular matrix is another unimodular matrix. A Positive unimodular matrix has det . The th Power of a Positive Unimodular Matrix

 (1)

is

 (2)

where
 (3)

and the are Chebyshev Polynomials of the Second Kind,
 (4)