The first aim of this note is to give a concise, but complete and self-contained, presentation of the fundamental theorems of Mori theory - the nonvanishing, base point free, rationality and cone theorems - using modern methods of multiplier ideals, Nadel vanishing, and the subadjunction theorem of Kawamata. The second aim is to write up a complete, detailed proof of existence of flips in dimension n assuming the minimal model program with scaling in dimension n-1.
We prove the existence of flips for $\mathbb Q$-factorial NQC generalized lc pairs, and the cone and contraction theorems for NQC generalized lc pairs. This answers a question of C. Birkar which was conjectured by J. Han and Z. Li. As an immediate application, we show that we can run the minimal model program for $\mathbb Q$-factorial NQC generalized lc pairs. In particular, we complete the minimal model program for $\mathbb Q$-factorial NQC generalized lc pairs in dimension $\leq 3$ and pseudo-effective $\mathbb Q$-factorial NQC generalized lc pairs in dimension $4$.
We provide a detailed proof of the validity of the Minimal Model Program for threefolds over excellent Dedekind separated schemes whose residue fields do not have characteristic 2 or 3.
A Minimal Model Program for $\mathbb{Q}$-Gorenstein varieties
本文的主要结果是已知的（V. V. Shokurov，非消灭定理，1985）。此外，O~Fujino最近考虑了非$\mathbb{Q}$ -阶乘MMP，在复曲面簇的情况下（复曲面收缩态射的等变完成，2006），对于klt对（特殊终止和约简到pl翻转，2007）以及更一般地对于对数典型对（极小模型程序的基础，2014）。在这里，我们重写证明这些结果中的一些，通过以下的证明Y。Kawamata，K. Matsuda和K. Matsuki（Introduction to the极小模型problem，1985）在$\mathbb{Q}$ -阶乘MMP中得到了相同的结果。并且，在$\mathbb{Q}$ -Gorenstein球面簇族中，我们肯定地回答了翻转的存在性和翻转序列的有限性问题.我为这篇论文的第一个版本道歉，我写的时候不知道这些结果已经存在。
We discuss the minimal model program for projective morphisms of complex analytic spaces. Roughly speaking, we show that the results obtained by Birkar--Cascini--Hacon--M\textsuperscript{c}Kernan hold true for projective morphisms between complex analytic spaces. We also treat some related topics.
We prove that many of the results of the LMMP hold for $3$-folds over fields of characteristic $p>5$ which are not necessarily perfect. In particular, the existence of flips, the cone theorem, the contraction theorem for birational extremal rays, and the existence of log minimal models. As well as pertaining to the geometry of fibrations of relative dimension $3$ over algebraically closed fields, they have applications to tight closure in dimension $4$.
We show the validity of two special cases of the four-dimensional Minimal Model Program in characteristic $p>5$: for contractions to $\mathbb{Q}$-factorial fourfolds and in families over curves ("semi-stable mmp"). We also provide their mixed characteristic analogues. As a corollary, we show that liftability of positive characteristic threefolds is stable under the minimal model program, and that liftability of three-dimensional Calabi-Yau varieties is a birational invariant. Our results are partially contingent upon the existence of log resolutions.
We examine the noncommutative minimal model program for orders on arithmetic surfaces, or equivalently, arithmetic surfaces enriched by a Brauer class $β$. When $β$ has prime index $p>5$, we show the classical theory extends with analogues of existence of terminal resolutions, Castelnuovo contraction and Zariski factorisation. We also classify $β$-terminal surfaces and Castelnuovo contractions, and discover new unexpected behaviour.
We provide several applications of the minimal model program to the local and global study of co-rank one foliations on threefolds. Locally, we prove a singular variant of Malgrange's theorem, a classification of terminal foliation singularities and the existence of separatrices for log canonical singularities. Globally, we prove termination of flips, a connectedness theorem on lc centres, a non-vanshing theorem and some hyperbolicity properties of foliations.
