Hostname: page-component-848d4c4894-wzw2p Total loading time: 0 Render date: 2024-04-30T22:58:24.541Z Has data issue: false hasContentIssue false

AN EFFECTIVE UPPER BOUND FOR ANTI-CANONICAL VOLUMES OF SINGULAR FANO THREEFOLDS

Published online by Cambridge University Press:  08 March 2024

Chen Jiang
Affiliation:
Shanghai Center for Mathematical Sciences & School of Mathematical Sciences, Fudan University, Shanghai, 200438, China (chenjiang@fudan.edu.cn)
Yu Zou*
Affiliation:
Yau Mathematical Sciences Center, Tsinghua University, Beijing, 100084, China

Abstract

For a real number $0<\epsilon <1/3$, we show that the anti-canonical volume of an $\epsilon $-klt Fano $3$-fold is at most $3,200/\epsilon ^4$, and the order $O(1/\epsilon ^4)$ is sharp.

Type
Research Article
Copyright
© The Author(s), 2024. Published by Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alexeev, V., Classification of log canonical surface singularities: Arithmetical proof, in Flips and abundance for algebraic threefolds, Papers from the Second Summer Seminar on Algebraic Geometry held at the University of Utah, Salt Lake City, Utah, Astérisque, 211, pp. 4758 (Societe Mathematique De France, Paris, 1992).Google Scholar
Ambro, F., Variation of log canonical thresholds in linear systems, Int. Math. Res. Not. IMRN 2016(14) (2016), 44184448.CrossRefGoogle Scholar
Birkar, C., Anti-pluricanonical systems on Fano varieties, Ann. of Math. (2) 190(2) (2019), 345463.Google Scholar
Birkar, C., Singularities of linear systems and boundedness of Fano varieties, Ann. of Math. (2) 193(2) (2021), 347405.CrossRefGoogle Scholar
Birkar, C., Anticanonical volume of Fano $4$ -folds, in Birational geometry, Kähler–Einstein metrics and Degenerations, Moscow, Shanghai and Pohang, June–November 2019, Springer Proceedings in Mathematics & Statistics, pp. 8593 (Springer, Switzerland, 2023).Google Scholar
Birkar, C., Cascini, P., Hacon, C. D. and McKernan, J., Existence of minimal models for varieties of log general type, J. Amer. Math. Soc. 23(2) (2010), 405468.CrossRefGoogle Scholar
Dolgachev, I. V., Classical Algebraic Geometry: A Modern View (Cambridge University Press, Cambridge, 2012).Google Scholar
Jiang, C., Bounding the volumes of singular weak log del Pezzo surfaces, Int. J. Math. 24(13) (2013), 1350110, 27 pp.Google Scholar
Jiang, C., On birational boundedness of Fano fibrations, Am. J. Math. 140(5) (2018), 12531276.Google Scholar
Jiang, C., Boundedness of anti-canonical volumes of singular log Fano threefolds, Comm. Anal. Geom. 29(7) (2021), 15711596.Google Scholar
Jiang, C. and Zou, Y., An effective upper bound for anti-canonical volumes of canonical $\mathbb{Q}$ -Fano three-folds, Int. Math. Res. Not. IMRN 2023(11) (2023), 92989318.Google Scholar
Kollár, J. and Mori, S., Birational geometry of algebraic varieties, in Cambridge Tracts in Mathematics, 134, pp. i-254 (Cambridge University Press, Cambridge, 1998).CrossRefGoogle Scholar
Lai, C.-J., Bounding volumes of singular Fano threefolds, Nagoya Math. J. 224(1) (2016), 3773.CrossRefGoogle Scholar
Lazarsfeld, R., Positivity in algebraic geometry, I, Classical setting: Line bundles and linear series, in Results in Mathematics and Related Areas, 3rd Series, A Series of Modern Surveys in Mathematics, 48, pp. i–387 (Springer-Verlag, Berlin, 2004).Google Scholar
Mori, S. and Prokhorov, Y. G., On $\mathbb{Q}$ -conic bundles, Publ. Res. Inst. Math. Sci. 44(2) (2008), 315369.CrossRefGoogle Scholar
Prokhorov, Y. G., Lectures on complements on log surfaces, in MSJ Memoirs, 10, pp. 1129 (Mathematical Society of Japan, Tokyo, 2001).Google Scholar
Prokhorov, Y. G., The degree of $\mathbb{Q}$ -Fano threefolds, Mat. Sb. 198(11) (2007), 153174. Translation in Sb. Math. 198(11–12) (2007), 1683–1702.Google Scholar
Zhang, Q., Rational connectedness of log $\mathbb{Q}$ -Fano varieties, J. Reine Angew. Math. 590 (2006), 131142.Google Scholar