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Algebraic construction of the sigma function for general Weierstrass curves

Algebraic Geometry 2023-04-24 v6 Exactly Solvable and Integrable Systems

Abstract

The Weierstrass curve XX is a smooth algebraic curve determined by the Weierstrass canonical form, yr+A1(x)yr1+A2(x)yr2++Ar1(x)y+Ar(x)=0y^r + A_{1}(x) y^{r-1} + A_{2}(x) y^{r-2} +\cdots + A_{r-1}(x) y + A_{r}(x)=0, where rr is a positive integer, and each AjA_j is a polynomial in xx with a certain degree. It is known that every compact Riemann surface has a Weierstrass curve XX which is birational to the surface. The form provides the projection ϖr:XP\varpi_r : X \to {\mathbb{P}} as a covering space. Let RX:=H0(X,OX())R_X := {\mathbb{H}}^0(X, {\mathcal{O}}_X(*\infty)) and RP:=H0(P,OP())R_{\mathbb{P}} := {\mathbb{H}}^0({\mathbb{P}}, {\mathcal{O}}_{\mathbb{P}}(*\infty)). Recently we have the explicit description of the complementary module RXcR_X^{\mathfrak{c}} of RPR_{\mathbb{P}}-module RXR_X, which leads the explicit expressions of the holomorphic one form except \infty, H0(P,AP()){\mathbb{H}}^0({\mathbb{P}}, {\mathcal{A}}_{\mathbb{P}}(*\infty)) and the trace operator pXp_X such that pX(P,Q)=δP,Qp_X(P, Q)=\delta_{P,Q} for ϖr(P)=ϖr(Q)\varpi_r(P)=\varpi_r(Q) for P,QX{}P, Q \in X\setminus\{\infty\}. In terms of them, we express the fundamental 2-form of the second kind Ω\Omega and a connection to the sigma functions for XX.

Keywords

Cite

@article{arxiv.2207.02690,
  title  = {Algebraic construction of the sigma function for general Weierstrass curves},
  author = {Jiryo Komeda and Shigeki Matsutani and Emma Previato},
  journal= {arXiv preprint arXiv:2207.02690},
  year   = {2023}
}

Comments

34pages. arXiv admin note: substantial text overlap with arXiv:2207.01905