2,798 research outputs found
Encoding algebraic power series
Algebraic power series are formal power series which satisfy a univariate
polynomial equation over the polynomial ring in n variables. This relation
determines the series only up to conjugacy. Via the Artin-Mazur theorem and the
implicit function theorem it is possible to describe algebraic series
completely by a vector of polynomials in n+p variables. This vector will be the
code of the series. In the paper, it is then shown how to manipulate algebraic
series through their code. In particular, the Weierstrass division and the
Grauert-Hironaka-Galligo division will be performed on the level of codes, thus
providing a finite algorithm to compute the quotients and the remainder of the
division.Comment: 35 page
Hurwitz numbers and intersections on moduli spaces of curves
This article is an extended version of preprint math.AG/9902104. We find an
explicit formula for the number of topologically different ramified coverings
of a sphere by a genus g surface with only one complicated branching point in
terms of Hodge integrals over the moduli space of genus g curves with marked
points.Comment: 30 pages (AMSTeX). Minor typos are correcte
Recommended from our members
Using formal methods to support testing
Formal methods and testing are two important approaches that assist in the development of high quality software. While traditionally these approaches have been seen as rivals, in recent
years a new consensus has developed in which they are seen as complementary. This article reviews the state of the art regarding ways in which the presence of a formal specification can be used to assist testing
An introduction to moduli stacks, with a view towards Higgs bundles on algebraic curves
This article is based in part on lecture notes prepared for the summer school
"The Geometry, Topology and Physics of Moduli Spaces of Higgs Bundles" at the
Institute for Mathematical Sciences at the National University of Singapore in
July of 2014. The aim is to provide a brief introduction to algebraic stacks,
and then to give several constructions of the moduli stack of Higgs bundles on
algebraic curves. The first construction is via a "bootstrap" method from the
algebraic stack of vector bundles on an algebraic curve. This construction is
motivated in part by Nitsure's GIT construction of a projective moduli space of
semi-stable Higgs bundles, and we describe the relationship between Nitsure's
moduli space and the algebraic stacks constructed here. The third approach is
via deformation theory, where we directly construct the stack of Higgs bundles
using Artin's criterion.Comment: 145 pages, AMS LaTeX, to appear in the NUS IMS Lecture Note Series on
The Geometry, Topology, and Physics of Moduli Spaces of Higgs Bundle
- …