The a-number of yn = xm + x over finite fields

This paper presents a formula for the [Formula: see text]-number of certain maximal curves characterized by the equation [Formula: see text] over the finite field [Formula: see text]. [Formula: see text]-number serves as an invariant for the isomorphism class of the [Formula: see text]-torsion group scheme. By utilizing the action of the Cartier operator on [Formula: see text], we establish a closed formula for the [Formula: see text]-number of [Formula: see text].