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Related papers: Hyperelliptic and trigonal Fano threefolds

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In this paper I study the rationality problem for Fano threefolds $X\subset \p^{p+1}$ of genus $p$, that are Gorenstein, with at most canonical singularities. The main results are: (1) a trigonal Fano threefold of genus $p$ is rational as…

Algebraic Geometry · Mathematics 2023-06-08 Ciro Ciliberto

We extend the known classification of threefolds of general type that are complete intersections to various classes of non-complete intersections, and find other classes of polarised varieties, including Calabi-Yau threefolds with canonical…

Algebraic Geometry · Mathematics 2022-10-28 Gavin Brown , Alexander Kasprzyk , Lei Zhu

We study global log canonical thresholds on anticanonically embedded quasismooth weighted Fano threefold hypersurfaces having terminal quotient singularities to prove the existence of a Kahler-Einstein metric on most of them, and to produce…

Algebraic Geometry · Mathematics 2007-06-18 Ivan Cheltsov

We classify Q-factorial Gorenstein Fano non-degenerate complete intersection threefolds in fake weighted projective spaces.

Algebraic Geometry · Mathematics 2025-10-14 Juergen Hausen , Paul Weiss

We propose a refined but natural notion of toric degenerations that respect a given embedding and show that within this framework a Gorenstein Fano variety can only be degenerated to a Gorenstein Fano toric variety if it is embedded via its…

Algebraic Geometry · Mathematics 2020-11-26 Christian Steinert

This paper classifies all toric Fano 3-folds with terminal singularities. This is achieved by solving the equivalent combinatoric problem; that of finding, up to the action of GL(3,Z), all convex polytopes in Z^3 which contain the origin as…

Algebraic Geometry · Mathematics 2022-10-28 Alexander Kasprzyk

We completely classify toric weakened Fano 3-folds, that is, smooth toric weak Fano 3-folds which are not Fano but are deformed to smooth Fano 3-folds. There exist exactly 15 toric weakened Fano 3-folds up to isomorphisms.

Algebraic Geometry · Mathematics 2007-05-23 Hiroshi Sato

An inductive approach to classifying toric Fano varieties is given. As an application of this technique, we present a classification of the toric Fano threefolds with at worst canonical singularities. Up to isomorphism, there are 674,688…

Algebraic Geometry · Mathematics 2019-08-15 Alexander M. Kasprzyk

For a generic anti-canonical hypersurface in each smooth toric Fano 4-fold with rank 2 Picard group, we prove there exist three isolated rational curves in it. Moreover, for all these 4-folds except one, the contractions of generic…

Algebraic Geometry · Mathematics 2010-12-21 Jinxing Xu

We classify non-factorial nodal Fano threefolds with $1$ node and class group of rank $2$.

Algebraic Geometry · Mathematics 2024-10-04 Ivan Cheltsov , Igor Krylov , Jesus Martinez-Garcia , Evgeny Shinder

A Fano-Enriques threefold is a three-dimensional non-Gorenstein Fano variety of index 1 with at most canonical singularities. We study the birational geometry of Fano-Enriques threefolds with terminal cyclic quotient singularities. We…

Algebraic Geometry · Mathematics 2023-01-19 Arman Sarikyan

We give a classification of smooth Fano fourfolds such that the base scheme of the anticanonical system is a smooth surface. As a consequence we show that there are exactly 22 deformation families of such manifolds and they are all obtained…

Algebraic Geometry · Mathematics 2025-10-27 Andreas Höring , Saverio Andrea Secci

We discuss families of hypersurfaces with isolated singularities in projective space with the property that the sum of the ranks of the rational homotopy and the homology groups is finite. They represent infinitely many distinct homotopy…

Algebraic Geometry · Mathematics 2026-02-02 A. Libgober

We classify toric Fano threefolds having at worst terminal singularities such that a rank of a $G$-invariant part of a class group equals one, where $G$ is a group acting on the variety by automorphisms.

Algebraic Geometry · Mathematics 2022-09-05 Arman Sarikyan

We show that mixed-characteristic and equi-characteristic small deformations of 3-dimensional canonical (resp. terminal) singularities with perfect residue field of characteristic $p>5$ are canonical (resp. terminal). We discuss…

Algebraic Geometry · Mathematics 2024-03-08 Fabio Bernasconi , Iacopo Brivio , Stefano Filipazzi

We classify Fano threefolds with only Gorenstein terminal singularities and Picard number greater than 1 satisfying an additional assumption that the $G$-invariant part of the Weil divisor class group is of rank 1 with respect to an action…

Algebraic Geometry · Mathematics 2016-01-29 Yuri Prokhorov

We find a relation between a cubic hypersurface $Y$ and its Fano variety of lines $F(Y)$ in the Grothendieck ring of varieties. We prove that if the class of an affine line is not a zero-divisor in the Grothendieck ring of varieties, then…

Algebraic Geometry · Mathematics 2014-06-27 Sergey Galkin , Evgeny Shinder

We classify three-dimensional nodal Fano varieties that are double covers of smooth quadrics branched over intersections with quartics acted on by finite simple non-abelian groups, and study their rationality.

Algebraic Geometry · Mathematics 2018-08-07 Victor Przyjalkowski , Constantin Shramov

We study Fano 3-folds with Fano index 2: that is, 3-folds X with rank Pic(X) = 1, Q-factorial terminal singularities and -K_X = 2A for an ample Weil divisor A. We give a first classification of all possible Hilbert series of such polarised…

Algebraic Geometry · Mathematics 2007-05-23 Gavin Brown , Kaori Suzuki

A complete classification is presented of elliptic and K3 fibrations birational to certain mildly singular complex Fano 3-folds. Detailed proofs are given for one example case, namely that of a general hypersurface X of degree 30 in…

Algebraic Geometry · Mathematics 2007-05-23 Daniel Ryder