NYJM Logo

New York Journal of Mathematics
Volume 31 (2025), 1667-1689

  

Livia Campo, Tiago Duarte Guerreiro, and Erik Paemurru

Blowups of smooth hypersurfaces, their birational geometry and divisorial stability

view    print


Published: November 25, 2025.
Keywords: Fano hypersurfaces, Mori dream spaces, divisorial stability, birational models.
Subject [2020]: 14E30,14J30,14J40,14J45,14J70,32Q20.

Abstract
Let X be a smooth n-dimensional Fano hypersurface in Pn+1 where n is greather than or equal to 3. Let Γ be a smooth positive-dimensional complete intersection of X, a hypersurface and one of more hyperplanes in Pn+1. Let Y -> X be the blowup of X along Γ. Let ϕ: Y -> X be the blowup of X along &Gamma. We describe the Mori chamber decomposition of Y and its associated birational models. In particular, we show that Y is a Mori dream space. We classify for which X and Γ the variety Y is a Fano manifold and, if X is a hyperplane, we classify the elementary Sarkisov links initiated by ϕ. Finally, we use this Mori chamber decomposition above to prove that certain Fano manifolds as above do not admit a Kahler-Einstein metric.

Acknowledgements

The first author was previously supported by the Korea Institute for Advanced Study (KIAS), grant No. MG087901. The second author was supported by Engineering and Physical Sciences Research Council (EPSRC) EP/V055399/1 and ERC StG Saphidir No. 101076412. The third author was supported by the Simons Investigator Award HMS, National Science Fund of Bulgaria, National Scientific Program "Excellent Research and People for the Development of European Science" (VIHREN), Project No. KP-06-DV-7 and this is a contribution to Project-ID 286237555 -- TRR 195 -- by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation).


Author information

Livia Campo
Institut fur Mathematik
Universitat Wien
Oskar-Morgenstern-Platz 1, 1090 Wien, Austria

livia.campo@univie.ac.at

Tiago Duarte Guerreiro
Departement Mathematik und Informatik
Universitat Basel
Spiegelgasse 1, 4051 Basel, Switzerland

tiago.duarteguerreiro@unibas.ch

Erik Paemurru
Institute of Mathematics and Informatics
Bulgarian Academy of Sciences
Acad. G. Bonchev Str. bl. 8, 1113, Sofia, Bulgaria;
former addresses: Mathematik und Informatik
Universitat des Saarlandes
66123 Saarbrucken, Germany,
and Department of Mathematics
University of Miami
Coral Gables, Florida 33146, USA

algebraic.geometry@runbox.com