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Minimal Weierstrass models and regular models of hyperelliptic curves

Qing Liu

Abstract

Let $C$ be a hyperelliptic curve of genus $g\ge 2$ over a discrete valuation field $K$ with perfect residue field. We study the minimal Weierstrass models of $C$. When there is more than one such model, we find interesting properties on the minimal regular model and the canonical model of $C$. For curves of genus $2$, we characterize the existence of the stable reduction in terms of the minimal Weierstrass models. When there is more than one such model, we can compute the Euler factor of $\mathrm{Jac}(C)$ and a volume form of the Néron model of $\mathrm{Jac}(C)$, using two specific minimal Weierstrass models.

Minimal Weierstrass models and regular models of hyperelliptic curves

Abstract

Let be a hyperelliptic curve of genus over a discrete valuation field with perfect residue field. We study the minimal Weierstrass models of . When there is more than one such model, we find interesting properties on the minimal regular model and the canonical model of . For curves of genus , we characterize the existence of the stable reduction in terms of the minimal Weierstrass models. When there is more than one such model, we can compute the Euler factor of and a volume form of the Néron model of , using two specific minimal Weierstrass models.
Paper Structure (20 sections, 57 theorems, 123 equations, 6 figures)

This paper contains 20 sections, 57 theorems, 123 equations, 6 figures.

Key Result

Theorem 1

Suppose $g$ is even and that $C$ has more than one minimal Weierstrass models. Then there exists an even $n\ge 2$ and a Weierstrass equation of $C$ such that the minimal Weierstrass models of $C$ are given by the equations (for even $0\le i\le n$): with $x_i=x/\pi^{i}$ and $y_i=y/\pi^{(g+1)i/2}$.

Figures (6)

  • Figure 1: $\Omega$, $\Omega'$ are the respective strict transforms of $Z_k$ and $Z'_k$.
  • Figure 2: The closed fiber of $(\widetilde{Z\vee Z'})_k$.
  • Figure 3: The closed fiber of $W_0\vee \cdots \vee W_n$.
  • Figure 4: Type IV$^*$ for $(W, p_0)$.
  • Figure 5: The closed fiber of the minimal regular model $\mathcal{C}$ of $C$.
  • ...and 1 more figures

Theorems & Definitions (126)

  • Theorem 1: Corollary \ref{['cor:equa_term']}, see also Theorem \ref{['chain-mwm']}
  • Theorem 2: Theorem \ref{['thm:bound_n']}
  • Theorem 3: Theorem \ref{['regular-even']}
  • Corollary 4: Corollary \ref{['cor:gl']}
  • Proposition 5: Proposition \ref{['prop:positive']}
  • Theorem 6: See Theorem \ref{['K1-K2']} and also Corollary \ref{['cor:g2_summary']}
  • Theorem 7: See Theorem \ref{['thm:stableg2']}
  • Theorem 8: Proposition \ref{['prop:volume']} and Theorem \ref{['thm:g2-Euler']}
  • Lemma 1.1
  • proof
  • ...and 116 more