Explicit equations for maximal curves as subcovers of the BM curve

Let r≥3 be an odd integer and Fq2r the finite field with q2r elements. A second generalisation of the Giulietti-Korchmáros maximal curve over Fq6 was presented in 2018 by Beelen and Montanucci, the so-called BM curve. This curve is maximal over Fq2r and isomorphic to the Giulietti-Korchmáros curve for r=3. In this paper, benefiting from suitable representations of the automorphism group of the BM curve, we construct explicit equations for...