Birational geometry of moduli spaces of configurations of points on the line

Autor: Michele Bolognesi, Alex Massarenti
Přispěvatelé: Institut Montpelliérain Alexander Grothendieck (IMAG), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Algebra & Number Theory
Algebra & Number Theory, Mathematical Sciences Publishers 2021, 15 (2), pp.513-544. ⟨10.2140/ant.2021.15.515⟩
ISSN: 1937-0652
DOI: 10.2140/ant.2021.15.515⟩
Popis: In this paper we study the geometry of GIT configurations of $n$ ordered points on $\mathbb{P}^1$ both from the the birational and the biregular viewpoint. In particular, we prove that any extremal ray of the Mori cone of effective curves of the quotient $(\mathbb{P}^1)^n//PGL(2)$, taken with the symmetric polarization, is generated by a one dimensional boundary stratum of the moduli space. Furthermore, we develop some technical machinery that we use to compute the canonical divisor and the Hilbert polynomial of $(\mathbb{P}^1)^n//PGL(2)$ in its natural embedding, and its group of automorphisms.
Comment: 22 pages (fixed one small inaccuracy)
Databáze: OpenAIRE