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Related papers: Remarks on defective Fano manifolds

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In this paper we classify n-dimensional Fano manifolds with index >=n-2 and positive second Chern character.

Algebraic Geometry · Mathematics 2012-06-08 Carolina Araujo , Ana-Maria Castravet

We study a particular class of rationally connected manifolds, $X\subset \p^N$, such that two general points $x,x' \in X$ may be joined by a conic contained in $X$. We prove that these manifolds are Fano, with $b_2\leq 2$. Moreover, a…

Algebraic Geometry · Mathematics 2012-09-11 Paltin Ionescu , Francesco Russo

We study some symplectic geometric aspects of rationally connected 4-folds. As a corollary, we prove that any smooth projective 4-fold symplectic deformation equivalent to a Fano 4-fold of pseudo-index at least 2 or a rationally connected…

Algebraic Geometry · Mathematics 2012-08-22 Zhiyu Tian

In this paper we prove that a regular foliation on a complex weak Fano manifold is algebraically integrable.

Algebraic Geometry · Mathematics 2015-10-19 Stéphane Druel

We study the cones of q-ample divisors on smooth complex varieties. In favourable cases, we identify a part where the closure of this cone and the nef cone have the same boundary. This is especially interesting for Fano (or almost Fano)…

Algebraic Geometry · Mathematics 2016-02-17 Robert Laterveer

This paper is a sequel to [arXiv:2403.18389]. We investigate the rationality problem for $\mathbf{Q}$-Fano threefolds of Fano index $\ge 3$.

Algebraic Geometry · Mathematics 2026-01-22 Yuri Prokhorov

We construct examples of Fano manifolds, which are defined over a field of positive characteristic, but not over $\com$.

Algebraic Geometry · Mathematics 2017-06-20 Ilya Karzhemanov

We classify all 1-nodal degenerations of smooth Fano threefolds with Picard number 1 (both nonfactorial and factorial) and describe their geometry. In particular, we describe a relation between such degenerations and smooth Fano threefolds…

Algebraic Geometry · Mathematics 2024-11-14 Alexander Kuznetsov , Yuri Prokhorov

In this paper we study mildly singular del Pezzo foliations on complex projective manifolds with Picard number one

Algebraic Geometry · Mathematics 2014-09-16 Carolina Araujo , Stéphane Druel

In a joint work with Saji, the second and the third authors gave an intrinsic formulation of wave fronts and proved a realization theorem of wave fronts in space forms. As an application, we show that the following four objects are…

Differential Geometry · Mathematics 2010-06-16 Huili Liu , Masaaki Umehara , Kotaro Yamada

In this paper we address Fano manifolds with positive higher Chern characters. They are expected to enjoy stronger versions of several of the nice properties of Fano manifolds. For instance, they should be covered by higher dimensional…

We classify Fano 3-folds with canonical Gorenstein singularities whose anticanonical linear system has no base points but does not give an embedding, and we classify anticanonically embedded Fano 3-folds with canonical Gorenstein…

Algebraic Geometry · Mathematics 2007-05-23 Ivan Cheltsov , Constantin Shramov , Victor Przyjalkowski

We exhibit several families of Fano threefolds with a multiplicative Chow-K\"unneth decomposition, in the sense of Shen-Vial. As a consequence, a certain tautological subring of the Chow ring of powers of these threefolds injects into…

Algebraic Geometry · Mathematics 2023-01-06 Robert Laterveer

We study complex projective manifolds X that admit surjective endomorphisms f:X->X of degree at least two. In case f is etale, we prove structure theorems that describe X. In particular, a rather detailed description is given if X is a…

Algebraic Geometry · Mathematics 2007-06-22 Marian Aprodu , Stefan Kebekus , Thomas Peternell

Let $X\subset P^n$ be a complex projective manifold of degree $d$ and arbitrary dimension. The main result of this paper gives a classification of such manifolds (assumed moreover to be connected, non-degenerate and linearly normal) in case…

Algebraic Geometry · Mathematics 2007-05-23 Paltin Ionescu

We continue our study of fixed loci of antisymplectic involutions on projective hyper-K\"ahler manifolds of $\mathrm{K3}^{[n]}$-type induced by an ample class of square 2 in the Beauville-Bogomolov-Fujiki lattice. We prove that if the…

Algebraic Geometry · Mathematics 2026-04-28 Laure Flapan , Emanuele Macrì , Kieran G. O'Grady , Giulia Saccà

In this paper, an update on the classification of smooth weak Fano threefolds with Picard number two and small anti-canonical maps is given. Geometric constructions are provided for previously open numerical cases by blowing up certain…

Algebraic Geometry · Mathematics 2025-01-22 Joseph Cutrone , Nicholas Marshburn

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 show that Fano 4-folds with Picard number 5 have Lefschetz defect 3 if and only if they are toric of combinatorial type K. We also find a characterization for such varieties in terms of Picard number of prime divisors. Moreover, we…

Algebraic Geometry · Mathematics 2020-07-22 Eleonora Anna Romano

In this work we deal with vector bundles of rank two on a Fano manifold $X$ with $b_2=b_4=1$. We study the nef and pseudoeffective cones of the corresponding projectivizations and how these cones are related to the decomposability of the…

Algebraic Geometry · Mathematics 2015-11-03 Roberto Muñoz , Gianluca Occhetta , Luis Solá Conde