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In [19], the authors give minimal embedded toric resolutions of ADE-singularities in C^3 by constructing regular refinements of their dual Newton polyhedrons with the elements of their embedded valuation sets derived from the jet schemes…

Algebraic Geometry · Mathematics 2025-03-12 Büşra Karadeniz Şen

We give a necessary and sufficient condition for the nonsingular projective toric variety associated to a building set to be weak Fano in terms of the building set.

Algebraic Geometry · Mathematics 2017-05-23 Yusuke Suyama

For a Fano threefold admitting a full exceptional collection of vector bundles of length four we show that all full exceptional collections consist of shifted vector bundles. We prove this via a detailed study of the group generated by…

Algebraic Geometry · Mathematics 2026-02-16 Anya Nordskova , Michel Van den Bergh

We construct families of non-toric $\mathbb{Q}$-factorial terminal Fano ($\mathbb{Q}$-Fano) threefolds of codimension $\geq 20$ corresponding to 54 mutation classes of rigid maximally mutable Laurent polynomials. From the point of view of…

Algebraic Geometry · Mathematics 2022-06-15 Liana Heuberger

We prove that the Fano variety of lines of a generic cubic fourfold containing a plane is isomorphic to a moduli space of twisted stable complexes on a K3 surface. On the other hand, we show that the Fano varieties are always birational to…

Algebraic Geometry · Mathematics 2011-12-26 Emanuele Macri , Paolo Stellari

Topological invariants such as characteristic classes are an important tool to aid in understanding and categorizing the structure and properties of algebraic varieties. In this note we consider the problem of computing a particular…

Algebraic Geometry · Mathematics 2017-11-15 Martin Helmer

Almost toric manifolds form a class of singular Lagrangian fibered symplectic manifolds that is a natural generalization of toric manifolds. Notable examples include the K3 surface, the phase space of the spherical pendulum and rational…

Symplectic Geometry · Mathematics 2007-05-23 Naichung Conan Leung , Margaret Symington

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

Toric orbifolds are a topological generalization of projective toric varieties associated to simplicial fans. We introduce some sufficient conditions on the combinatorial data associated to a toric orbifold to ensure the existence of an…

Algebraic Geometry · Mathematics 2021-06-29 Soumen Sarkar , V. Uma

This work deals with the study of embeddings of toric Calabi-Yau fourfolds which are complex cones over the smooth Fano threefolds. In particular, we focus on finding various embeddings of Fano threefolds inside other Fano threefolds and…

High Energy Physics - Theory · Physics 2016-11-23 Siddharth Dwivedi

Birational Calabi-Yau threefolds in the same deformation family provide a `weak' counterexample to the global Torelli problem, as long as they are not isomorphic. In this paper, it is shown that deformations of certain desingularized…

Algebraic Geometry · Mathematics 2009-10-31 Balazs Szendroi

We give an explicit construction for the extension of a symmetric determinantal quartic K3 surface to a Fano 6-fold. Remarkably, the moduli of the 6-fold extension are in one-to-one correspondence with the moduli of the quartic surface. As…

Algebraic Geometry · Mathematics 2009-10-01 Stephen Coughlan

We study the structure of rational Picard groups of hypersurfaces of toric varieties. By using the fan structure associated to the ambient toric variety, an explicit basis of the Picard group is described by certain combinatorial data. We…

Algebraic Geometry · Mathematics 2011-07-26 Shi-shyr Roan

We propose new definitions of integral, reduced, and normal superrings and superschemes to properly establish the notion of a supervariety. We generalize several results about classical reduced rings and varieties to the supergeometric…

Algebraic Geometry · Mathematics 2025-03-11 Eric Jankowski

Motivated by bases of representations compatible with the PBW filtration for basic Lie superalgebras by Kus and Fourier, we generalise the construction of degenerations of flag varieties via favourable modules to the super setup. In the…

Algebraic Geometry · Mathematics 2026-05-07 Ibrahim Ahmad

We characterize the birational geometry of some hyperk\"ahler fourfolds of Picard rank $3$ obtained as the Fano varieties of lines on cubic fourfolds containing pairs of cubic scrolls. In each of the two cases considered, we identify all of…

Algebraic Geometry · Mathematics 2025-09-10 Corey Brooke , Sarah Frei , Lisa Marquand , Xuqiang Qin

Using deformation theory of rational curves, we prove a conjecture of Sommese on the extendability of morphisms from ample subvarieties when the morphism is a smooth (or mildly singular) fibration with rationally connected fibers. We apply…

Algebraic Geometry · Mathematics 2020-11-23 Tommaso de Fernex , Chung Ching Lau

In this paper we construct a spectral sequence computing a modified version of morphic cohomology of a toric variety (even when it is singular) in terms of combinatorial data coming from the fan of the toric variety.

Algebraic Geometry · Mathematics 2010-01-19 Abdó Roig-Maranges

We classify all smooth projective toric surfaces $S$ containing exactly one exceptional curve. We show that every such surface $S$ is isomorphic to either $\mathbb{F}_1$ or a surface $S_r$ defined by a rational number $r \in \mathbb{Q}…

Algebraic Geometry · Mathematics 2024-12-17 Victor Batyrev

Resolutions of the diagonal of toric varieties has been an active area of study since Beilinson's celebrated resolution of the diagonal for $\PP^n$ and the disproof of King's conjecture. The author generalized a cellular resolution of the…

Algebraic Geometry · Mathematics 2025-12-16 Reginald Anderson