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Related papers: K-moduli of log Fano complete intersections

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We study the behaviour on some nodal hyperplanes of the isomorphism, described in a paper of 2019 by Boissi\`ere, Camere and Sarti, between the moduli space of smooth cubic threefolds and the moduli space of hyperk\"ahler fourfolds of…

Algebraic Geometry · Mathematics 2025-03-27 Lucas Li Bassi

By work of Looijenga and others, one has a good understanding of the relationship between GIT and Baily-Borel compactifications for the moduli spaces of degree 2 K3 surfaces, cubic fourfolds, and a few other related examples. The…

Algebraic Geometry · Mathematics 2019-08-15 Radu Laza , Kieran G. O'Grady

In this article, we study the geometric invariant theory (GIT) compactification of quintic threefolds. We study singularities, which arise in non-stable quintic threefolds, thus giving a partial description of the stable locus. We also give…

Algebraic Geometry · Mathematics 2010-10-20 Chirag Lakhani

We characterize the image of the period map for cubic fourfolds with at worst simple singularities as the complement of an arrangement of hyperplanes in the period space. It follows then that the GIT compactification of the moduli space of…

Algebraic Geometry · Mathematics 2012-03-20 Radu Laza

There have been major developments in the theory of moduli of varieties in the past decade, essentially settling the construction of moduli spaces of log canonically polarized slc pairs and moduli spaces of K-polystable log Fano pairs.…

Algebraic Geometry · Mathematics 2026-02-25 Kristin DeVleming

We present some applications of the deformation theory of toric Fano varieties to K-(semi/poly)stability of Fano varieties. First, we present two examples of K-polystable toric Fano 3-fold with obstructed deformations. In one case, the…

Algebraic Geometry · Mathematics 2021-09-02 Anne-Sophie Kaloghiros , Andrea Petracci

We use geometric invariant theory (GIT) to construct a large class of compactifications of the moduli space M_{0,n}. These compactifications include many previously known examples, as well as many new ones. As a consequence of our GIT…

Algebraic Geometry · Mathematics 2016-02-08 Noah Giansiracusa , David Jensen , Han-Bom Moon

We prove a decomposition theorem for the quantum cohomology of variations of GIT quotients. More precisely, for any reductive group $G$ and a simple $G$-VGIT wall-crossing $X_- \dashrightarrow X_+$ with a wall $S$, we show that the quantum…

Algebraic Geometry · Mathematics 2025-08-22 Zhaoxing Gu , Song Yu , Tony Yue YU

We complete the analysis on the birational rigidity of quasismooth Fano 3-fold deformation families appearing in the Graded Ring Database as a complete intersection. When such a deformation family $X$ has Fano index at least 2 and is…

Algebraic Geometry · Mathematics 2023-01-18 Tiago Duarte Guerreiro

We introduce and study smooth compactifications of the moduli space of n labeled points with weights in projective space, which have normal crossings boundary and are defined as GIT quotients of the weighted Fulton-MacPherson…

Algebraic Geometry · Mathematics 2017-04-10 Patricio Gallardo , Evangelos Routis

We find Fano threefolds $X$ admitting K\"ahler-Ricci solitons (KRS) with non-trivial moduli, which are $\mathbb{T}$-varieties of complexity two. More precisely, we show that the weighted K-stability of $(X,\xi_0)$ (where $\xi_0$ is the…

Algebraic Geometry · Mathematics 2025-08-01 Minghao Miao , Linsheng Wang

We compute and compare the (intersection) cohomology of various natural geometric compactifications of the moduli space of cubic threefolds: the GIT compactification and its Kirwan blowup, as well as the Baily-Borel and toroidal…

Algebraic Geometry · Mathematics 2024-04-25 Sebastian Casalaina-Martin , Samuel Grushevsky , Klaus Hulek , Radu Laza

We prove that the quotient of a klt type singularity by a reductive group is of klt type. In particular, given a klt variety $X$ endowed with the action of a reductive group $G$ and admitting a quasi-projective good quotient $X\rightarrow…

Algebraic Geometry · Mathematics 2024-08-21 Lukas Braun , Daniel Greb , Kevin Langlois , Joaquín Moraga

We explicitly determine the optimal degenerations of Fano threefolds $X$ in family No 2.23 of Mori-Mukai's list as predicted by the Hamilton-Tian conjecture. More precisely, we find a special degeneration $(\mathcal{X}, \xi_0)$ of $X$ such…

Algebraic Geometry · Mathematics 2026-04-14 Minghao Miao , Linsheng Wang

Looijenga has introduced new compactifications of locally symmetric varieties that give a complete understanding of the period map from the GIT moduli space of plane sextics to the Baily-Borel compactification of the moduli space polarized…

Algebraic Geometry · Mathematics 2017-11-09 Radu Laza , Kieran O'Grady

Explicit birational geometry of 3-folds represents a second phase of Mori theory, going beyond the foundational work of the 1980s. This paper is a tutorial and colloquial introduction to the explicit classification of Fano 3-folds (Q-Fano…

Algebraic Geometry · Mathematics 2007-05-23 Selma Altınok , Gavin Brown , Miles Reid

In this paper, we study the moduli space of quasi-polarized complex K3 surfaces of degree 6 and 8 via geometric invariant theory. The general members in such moduli spaces are complete intersections in projective spaces and we have natural…

Algebraic Geometry · Mathematics 2020-10-07 Zhiyuan Li , Zhiyu Tian

In this paper we describe the geometry of the 2m-dimensional Fano manifold G parametrizing (m-1)-planes in a smooth complete intersection Z of two quadric hypersurfaces in the complex projective space P^{2m+2}, for m>0. We show that there…

Algebraic Geometry · Mathematics 2018-03-16 Carolina Araujo , Cinzia Casagrande

The K-moduli space of Fano varieties has been popular in recent research of algebraic geometry. There has been a lot of progress in dimension 3 and we will try to construct explicitly a compactified K-moduli space for the Fano family 2.24.

Algebraic Geometry · Mathematics 2023-09-29 Dongchen Jiao

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…