On a Galois cover of the Hermitian curve of genus $\mathfrak{g}=\frac{1}{8}(q-1{)}^2$

Abstract

In the study of algebraic curves with many points over a finite field, a well known general problem is to understanding better the properties of ${\mathbb{F}}_{q^2}$-maximal curves whose genera fall in the higher part of the spectrum of the genera of all ${\mathbb{F}}_{q^2}$-maximal curves. This problem is still open for genera smaller than $\lfloor \frac{1}{6}(q^2-q+4)\rfloor$. In this paper we consider the case of $\mathfrak{g}=\frac{1}{8}(q-1{)}^2$ where $q\equiv 1(\mathrm{mod}4)$ and the curve is the Galois cover of the Hermitian curve w.r.t to a cyclic automorphism group of order $4$. Our contributions concern Frobenius embedding, Weierstrass semigroups and automorphism groups.