SearcharxivSearch

arXiv · alg-geom/9608030

Genus one enumerative invariants in P^n with fixed j invariant

Abstract

We prove recursive formulas for $τ_d$, the number of degree $d$ elliptic curves with fixed j-invariant in P^n. We use analysis to relate the classical invariant $τ_d$ to the genus one perturbed invariant $RT_{1,d}$ defined recently by Ruan and Tian (the later invariant can be computed inductively). By considering a sequence of perturbations converging to zero, we then apply Taubes' Obstruction Bundle method to compute the difference between the two invariants.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Eleny Ionel. 1996-08-26. Genus one enumerative invariants in P^n with fixed j invariant. https://arxiv.org/abs/alg-geom/9608030

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Classification of Varieties with Canonical Curve Section via Gaussian maps on Canonical Curves

Let $C \subset P^{g-1}$ be a smooth canonical curve of genus $g \geq 3$. The purpose of this article is to further develop a method to classify varieties having $C$ as their curve section, using Gaussian map computations. In a previous article a careful analysis of the degeneration to the cone over the hyperplane section was made for _prime_ Fano threefolds, that is Fano threefolds whose Picard group is generated by the hyperplane bundle. In this article we extend this method and classify Fano threefolds of higher index (which still have Picard number one). We are also able to classify Mukai varieties, i.e. varieties of dimension four or more with canonical curve sections.

alg-geom

Boundedness and $K^2$ for log surfaces

Let $ε, C$ be two positive real numbers, and $\mathcal C \subset \mathbb R$ be a DCC (descending chain condition) set. Let $(X, B = \sum b_j B_j)$ denote a projective surface with an $\mathbb R$-divisor. Then (1) The class $\{X\}$ of surfaces for which there exists a divisor $B$ such that $(X,B)$ is $ε$-log terminal and $-(K_X + B)$ is nef (excluding only those for which at the same time $K_X\equiv 0$, $B=0$, and $X$ has at worst Du Val singularities), is bounded. (2) The set $\{(K_X + B)^2\}$ of squares for the semi log canonical pairs $(X, B)$ with ample $K_X + B$ and $b_j \in \mathcal C$, is a DCC set. (3) The class $\{(X,B)\}$ of pairs such that $(X, B)$ is semi log canonical, $K_X + B$ is ample, $(K_X + B)^2 = C$ and $b_j \in \mathcal C$, is bounded.

alg-geom