On the singularity of the Demjanenko matrix of quotients of Fermat curves

Francesc Fite, Igor E. Shparlinski

Given a prime $\ell \ge 3$ and a positive integer $k\le \ell -2$, one can define a matrix $D_{k,\ell }$, the so-called Demjanenko matrix, whose rank is equal to the dimension of the…