On the principal minors of Fourier matrices

Andrei Caragea, Dae Gwan Lee

For the $N$-dimensional Fourier matrix ${\mathcal{F}}_N$, we prove that if $N\ge 4$ is square-free, then every $2\times 2$ and $3\times 3$ principal minor of ${\mathcal{F}}_N$ is non…