A minor is a determinant of a square matrix formed from a bigger square matrix by removing rows and columns. A minor having value zero means that its associated submatrix is non invertible.
The amount of zero valued minors of a size n discrete Fourier transform matrix seems to depend on the amount of divisors of n where more zero valued minors are found with more divisors.
See an example in radio communication.
How can it be shown?
How can the amount of zero valued minors be determined?