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arXiv · 2605.14583

Weierstrass semigroups at totally ramified places of degree one on Kummer extensions

Huachao Zhang·Chang-An Zhao
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Abstract

We explicitly describe the set of gaps and the Weierstrass semigroup at a totally ramified place of degree one on a Kummer extension defined by the affine equation $y^m = f(x)$ over $K$, an algebraic extension of $\mathbb{F}_q$, where $f(x)\in K(x)$. Our description takes a unified form for distinct totally ramified places of degree one. We then provide a necessary and sufficient condition for the Weierstrass semigroup at a totally ramified place of degree one to be symmetric. Furthermore, we investigate the minimal generating set of the Weierstrass semigroups at many totally ramified places of degree one. We not only explicitly describe the minimal generating set, but also construct functions whose pole divisors have coefficients lying in the set. Finally, we apply our results to specific Kummer extensions, including function fields of GGS curves and subcovers of the BM curve.

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Huachao Zhang, Chang-An Zhao. 2026-05-14. Weierstrass semigroups at totally ramified places of degree one on Kummer extensions. https://arxiv.org/abs/2605.14583

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