English

Boundedness and $K^2$ for log surfaces

alg-geom 2017-02-20 v3 Algebraic Geometry

Abstract

Let ϵ,C\epsilon, C be two positive real numbers, and CR\mathcal C \subset \mathbb R be a DCC (descending chain condition) set. Let (X,B=bjBj)(X, B = \sum b_j B_j) denote a projective surface with an R\mathbb R-divisor. Then (1) The class {X}\{X\} of surfaces for which there exists a divisor BB such that (X,B)(X,B) is ϵ\epsilon-log terminal and (KX+B)-(K_X + B) is nef (excluding only those for which at the same time KX0K_X\equiv 0, B=0B=0, and XX has at worst Du Val singularities), is bounded. (2) The set {(KX+B)2}\{(K_X + B)^2\} of squares for the semi log canonical pairs (X,B)(X, B) with ample KX+BK_X + B and bjCb_j \in \mathcal C, is a DCC set. (3) The class {(X,B)}\{(X,B)\} of pairs such that (X,B)(X, B) is semi log canonical, KX+BK_X + B is ample, (KX+B)2=C(K_X + B)^2 = C and bjCb_j \in \mathcal C, is bounded.

Keywords

Cite

@article{arxiv.alg-geom/9402007,
  title  = {Boundedness and $K^2$ for log surfaces},
  author = {Valery Alexeev},
  journal= {arXiv preprint arXiv:alg-geom/9402007},
  year   = {2017}
}

Comments

This version: a TeX fix only. The old TeX version did not work with pdflatex, producing strange characters