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Related papers: Boundedness theorem for Fano log-threefolds

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We compute global log canonical thresholds of certain birationally bi-rigid Fano 3-folds embedded in weighted projective spaces as complete intersections of codimension 2 and prove that they admit an orbifold K\"{a}hler-Einstein metric and…

Algebraic Geometry · Mathematics 2019-03-19 In-Kyun Kim , Takuzo Okada , Joonyeong Won

The main result of this paper is a universal finiteness theorem for the set of all small dilatation pseudo-Anosov homeomorphisms, ranging over all surfaces. More precisely, we consider pseudo-Anosovs F:S to S with |chi(S)| log(lambda(F))…

Geometric Topology · Mathematics 2009-05-05 Benson Farb , Christopher J. Leininger , Dan Margalit

We answer an open question concerning the boundedness of canonical fiber spaces in high dimensions and prove the following: for any set of integers $n\geq 3$, $0<d<n$ and $N>0$, there exists a nonsingular projective $n$-fold $X$ of general…

Algebraic Geometry · Mathematics 2017-05-04 Meng Chen , Zhi Jiang

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 give a necessary and sufficient condition for a generalized Bott manifold to be Fano or weak Fano. As a consequence we characterize Fano Bott manifolds.

Algebraic Geometry · Mathematics 2018-11-16 Yusuke Suyama

In this paper, we prove a similar result to the fundamental theorem of regular surfaces in classical differential geometry, which extends the classical theorem to the entire class of singular surfaces in Euclidean 3-space known as frontals.…

Differential Geometry · Mathematics 2019-10-08 Tito Alexandro Medina Tejeda

We show that any Fano fivefold with canonical Gorenstein singularities has an effective anticanonical divisor. Moreover,if a general element of the anticanonical system is reduced, then it has canonical singularities. We also prove…

Algebraic Geometry · Mathematics 2020-02-10 Andreas Höring , Robert Śmiech

We construct well-formed and quasismooth terminal Fano 4-folds of index 1 in low codimension containing at worst isolated orbifold points. We provide a certain classification of these varieties where their images under the anitcanonical…

Algebraic Geometry · Mathematics 2025-06-30 Muhammad Imran Qureshi

We provide examples of smooth three-dimensional Fano complete intersections of dergee 2, 4, 6, and 8 that have coregularity 0. Considering the main theorem of arXiv:2309.16784 on the remaining 101 families of smooth Fano threefolds, our…

Algebraic Geometry · Mathematics 2024-09-05 Olzhas Zhakupov

We construct prime Fano manifolds from spin representations of $Spin_n$ for $n\le 14$. In this range, and if $n\ne 13$, the projectivizations of these representations are prehomogeneous, and we deduce that our Fano manifolds are locally…

Algebraic Geometry · Mathematics 2026-05-28 Alessandro Frassineti , Laurent Manivel

We prove:(1) the existence, for every integer n > 3, of a noncompact smooth n-dimensional topological manifold whose diffeomorphism group contains an isomorphic copy of every finitely presented group; (2) a finiteness theorem on finite…

Group Theory · Mathematics 2014-01-07 Vladimir L. Popov

We study degree of irrationality of quasismooth anticanonically embedded weighted Fano 3-fold hypersurfaces that have terminal singularities.

Algebraic Geometry · Mathematics 2022-10-27 Ivan Cheltsov , Jihun Park

We prove categorical Torelli theorems for four families of Fano double covers with Picard rank greater than 1. Among these is the family of Verra fourfolds. The other three families manifest as double covers of Fano threefolds, branched in…

Algebraic Geometry · Mathematics 2026-05-18 Augustinas Jacovskis , Reinder Meinsma

We survey what is known about Fano threefold weighted complete intersections from the point of view of birational rigidity.

Algebraic Geometry · Mathematics 2025-08-20 Tiago Duarte Guerreiro , Takuzo Okada

We study the birational boundedness of special fibers of log Calabi-Yau fibrations and Fano fibrations. We show that for a locally stable family of Fano varieties or polarised log Calabi-Yau pairs over a curve, if the general fiber…

Algebraic Geometry · Mathematics 2023-02-17 Junpeng Jiao

In this paper, we give some results on the birational geometry of varieties of Fano type and boundedness problems in positive characteristic, including a result ensuring that boundedness is invariant under normalizations, a canonical bundle…

Algebraic Geometry · Mathematics 2025-03-10 Xintong Jiang

A V_{12} Fano threefold is a smooth Fano threefold X of index 1 with Pic X = Z and (-K_X)^3=12. We show that the bounded derived category of coherent sheaves on any V_{12} threefold X admits a semiorthogonal decomposition consisting of two…

Algebraic Geometry · Mathematics 2007-05-23 Alexander Kuznetsov

We extend the concept of orbifold to that of branchfold, in order to allow any cone singularities with rational angles, and show why branchfolds naturally fit in the theory of branched coverings. Then, we obtain a geometric goodness theorem…

Geometric Topology · Mathematics 2008-06-20 Riccardo Piergallini , Giacomo Tomassoni

The main purpose of this paper is twofold. We first want to analyze in details the meaningful geometric aspect of the method introduced in the previous paper [12], concerning regularity of families of irreducible, nodal "curves" on a…

Algebraic Geometry · Mathematics 2007-05-23 Flaminio Flamini

We prove that for every nonnegative integer $g$, there exists a bound on the number of ends of a complete, embedded minimal surface $M$ in $\mathbb{R}^3$ of genus $g$ and finite topology. This bound on the finite number of ends when $M$ has…

Differential Geometry · Mathematics 2019-09-19 William H. Meeks , Joaquin Perez , Antonio Ros