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Related papers: On smooth Fano threefolds with coregularity zero

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The existence is proved of two new families of locally Cohen-Macaulay sextic threefolds in $\mathbb{P}^5$, which are not quadratically normal. These threefolds arise naturally in the realm of first order congruences of lines as focal loci…

Algebraic Geometry · Mathematics 2014-06-13 Pietro De Poi , Emilia Mezzetti

We prove that every quasi-smooth hypersurface in the 95 families of weighted Fano threefold hypersurfaces is birationally rigid.

Algebraic Geometry · Mathematics 2017-02-14 Ivan Cheltsov , Jihun Park

Over an algebraically closed field of positive characteristic, we classify smooth Fano threefolds of Picard number one whose anti-canonical linear systems are not very ample. Furthermore, we also prove that an anti-canonically embedded Fano…

Algebraic Geometry · Mathematics 2026-03-13 Hiromu Tanaka

We prove that smooth Fano 3-folds in the families 2.18 and 3.4 are K-stable.

Algebraic Geometry · Mathematics 2023-04-25 Ivan Cheltsov , Kento Fujita , Takashi Kishimoto , Jihun Park

We produce a list of 64 families of Fano fourfolds of K3 type, extracted from our database of at least 634 Fano fourfolds constructed as zero loci of general global sections of completely reducible homogeneous vector bundles on products of…

Algebraic Geometry · Mathematics 2025-05-23 Marcello Bernardara , Enrico Fatighenti , Laurent Manivel , Fabio Tanturri

We establish the vanishing of the third unramified cohomology group for many types of Fano hypersurfaces in projective space over an algebraically closed field of arbitrary characteristic, and over a finite field. For cubic hypersurfaces…

Algebraic Geometry · Mathematics 2017-10-18 Jean-Louis Colliot-Thélène

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

We classify families of free rational curves on all smooth Fano threefolds over the complex numbers. In particular, we prove the family of very free rational curves representing any fixed numerical curve class is either irreducible or…

Algebraic Geometry · Mathematics 2024-09-04 Andrew Burke , Eric Jovinelly

Based on the former parts, we classify smooth Fano threefolds of positive characteristic.

Algebraic Geometry · Mathematics 2025-12-04 Hiromu Tanaka

The family of smooth Fano 3-folds with Picard rank 1 and anticanonical volume 4 consists of quartic 3-folds and of double covers of the 3-dimensional quadric branched along an octic surface. They can all be parametrised as complete…

Algebraic Geometry · Mathematics 2024-04-09 Hamid Abban , Ivan Cheltsov , Alexander Kasprzyk , Yuchen Liu , Andrea Petracci

We study a family of 3-dimensional Lorentz manifolds. Some members of the family are 0-curvature homogeneous, 1-affine curvature homogeneous, but not 1-curvature homogeneous. Some are 1-curvature homogeneous but not 2-curvature homogeneous.…

Differential Geometry · Mathematics 2007-05-23 P. Gilkey , S. Nikcevic

We study K-stability of smooth Fano threefolds of Picard rank $2$ and degree $22$ which can be obtained by blowing up a smooth complete intersection of two quadrics in $\mathbb{P}^5$ along a conic. We also describe the automorphism groups…

We study smoothings of Fano threefolds. We prove that the Picard number remains constant in the case of terminal Gorenstein singularities.

Algebraic Geometry · Mathematics 2007-05-23 Priska Jahnke , Ivo Radloff

In this article, we prove that any $\Bbb Q$-factorial weak Fano 3-fold with only terminal singularities has a smoothing.

Algebraic Geometry · Mathematics 2007-05-23 Tatsuhiro Minagawa

T.Kishimoto raised the problem to classify all compactifications of contractible affine 3-folds into smooth Fano 3-folds with second Betti number two and classified such compactifications whose log canonical divisors are not nef. In this…

Algebraic Geometry · Mathematics 2017-08-10 Masaru Nagaoka

We classify Fano threefolds with only terminal singularities whose canonical class is Cartier and divisible by 2, and satisfying an additional assumption that the $G$-invariant part of the Weil divisor class group is of rank 1 with respect…

Algebraic Geometry · Mathematics 2013-08-06 Yuri Prokhorov

We determine birational superrigidity for a quasi-smooth prime Fano 3-fold of codimension 4 with no projection centers. In particular we prove birational superrigidity for Fano 3-folds of codimension 4 with no projection centers which are…

Algebraic Geometry · Mathematics 2020-03-18 Takuzo Okada

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 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 give new proofs of the K-polystability of two smooth Fano threefolds. One of them is a~smooth divisor in $\mathbb{P}^1\times\mathbb{P}^1\times\mathbb{P}^2$ of degree $(1,1,1)$, which is unique up to isomorphism. Another one is the~blow…

Algebraic Geometry · Mathematics 2021-07-13 Ivan Cheltsov , Hendrik Süß