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JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb., 2021 Volume 212, Number 3, Pages 20–38 (Mi sm9446)

This article is cited in 1 paper

Singularities on toric fibrations

C. Birkara, Y. Chenb

a Department of Pure Mathematics and Mathematical Statistics, Centre for Mathematical Sciences, Cambridge University, Cambridge, UK
b Hua Loo-Keng Key Laboratory of Mathematics, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, P.R. China

Abstract: In this paper we investigate singularities on toric fibrations. In this context we study a conjecture of Shokurov (a special case of which is due to M\textsuperscript{c}Kernan) which roughly says that if $(X,B)\to Z$ is an $\varepsilon$-lc Fano-type log Calabi-Yau fibration, then the singularities of the log base $(Z,B_Z+M_Z)$ are bounded in terms of $\varepsilon$ and $\dim X$ where $B_Z$ and $M_Z$ are the discriminant and moduli divisors of the canonical bundle formula. A corollary of our main result says that if $X\to Z$ is a toric Fano fibration with $X$ being $\varepsilon$-lc, then the multiplicities of the fibres over codimension one points are bounded depending only on $\varepsilon$ and $\dim X$.
Bibliography: 20 titles.

Keywords: toric varieties, Shokurov's conjecture, singularities of pairs.

UDC: 512.761

MSC: Primary 14B05, 14M25; Secondary 14E30

Received: 15.05.2020 and 14.10.2020

DOI: 10.4213/sm9446


 English version:
Sbornik: Mathematics, 2021, 212:3, 288–304

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© Steklov Math. Inst. of RAS, 2024