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Let $\mathcal{L}$ be a line bundle on a smooth and proper scheme $X$ over $S$. We compute, in the case where $S$ is smooth over a field of characteristic $0$, the virtual fundamental class of the closed subset of $S$ consisting of those…

Algebraic Geometry · Mathematics 2026-02-12 Amira Tlemsani

In this note, we extend the theories of the canonical bundle formula and adjunction to the case of generalized pairs. As an application, we study a particular case of a conjecture by Prokhorov and Shokurov.

Algebraic Geometry · Mathematics 2021-08-12 Stefano Filipazzi

We apply our earlier work on the higher-dimensional analogue of the Mumford conjecture to two questions. Inspired by work of Ebert we prove non-triviality of certain characteristic classes of bundles of smooth closed manifolds. Inspired by…

Algebraic Topology · Mathematics 2013-04-23 Soren Galatius , Oscar Randal-Williams

In this article, we first describe codimension two regular foliations with numerically trivial canonical class on complex projective manifolds whose canonical class is not numerically effective. Building on a recent algebraicity criterion…

Algebraic Geometry · Mathematics 2023-06-22 Stéphane Druel

We study the moduli functor of flat bundles on smooth, possibly non-proper, algebraic variety $X$ (over a field of characteristic zero). For this we introduce the notion of \emph{formal boundary} of $X$, denoted by $\partial X$, which is a…

Algebraic Geometry · Mathematics 2021-09-02 Tony Pantev , Bertrand Toën

Let H be a semisimple algebaric group and let X be a smooth projective curve defined over an algebraically closed field k. In the first part of this paper we show that the moduli of semistable principal H-bundles exists once given a…

Algebraic Geometry · Mathematics 2007-05-23 V. Balaji , A. J. Parameswaran

In this paper we study the sections of the canonical line bundle on the moduli space of parabolic semistable vector bundles with trivial determinant and fixed parabolic structure of type $\underline{\lambda}=(\lambda_1,..., \lambda_s)$…

Algebraic Geometry · Mathematics 2007-05-23 Arzu Boysal

We show that the M-canonical map of an n-dimensional complex projective manifold X of Kodaira dimension two is birational to an Iitaka fibration for a computable positive integer M. M depends on the index b of a general fibre F of the…

Algebraic Geometry · Mathematics 2018-06-20 Eckart Viehweg , De-Qi Zhang

We show that if M is a surface bundle over S^1 with fiber of genus 2, then for any integer n, M has a finite cover tilde(M) with b_1(tilde(M)) > n. A corollary is that M can be geometrized using only the `non-fiber' case of Thurston's…

Geometric Topology · Mathematics 2014-11-11 Joseph D Masters

We study Miyaoka-type semistability criteria for principal Higgs G-bundles E on complex projective manifolds of any dimension. We prove that E has the property of being semistable after pullback to any projective curve if and only if…

Algebraic Geometry · Mathematics 2011-02-04 Ugo Bruzzo , Beatriz Graña Otero

We study positivity properties of the moduli (b-)divisor associated to a relative log pair $(X,B)/Y$ with relatively trivial log canonical class.

Algebraic Geometry · Mathematics 2007-05-23 Florin Ambro

The classical Serre-Swan theorem asserts that any finitely generated projective module over the algebra $C^\infty(M)$ of smooth functions of a manifold $M$ can be realized as the sections of a vector bundle over $M$. In this article, we…

Differential Geometry · Mathematics 2025-11-26 Alfonso Garmendia , David Miyamoto , Leonid Ryvkin

Let $X$ be a smooth projective curve of genus $g \geq 2$ and $M$ be the moduli space of rank 2 stable vector bundles on $X$ whose determinants are isomorphic to a fixed odd degree line bundle $L$. There has been a lot of works studying the…

Algebraic Geometry · Mathematics 2021-06-10 Kyoung-Seog Lee , M. S. Narasimhan

Given a Fano type log Calabi-Yau fibration $(X,B)\to Z$ with $(X,B)$ being $\epsilon$-lc, the first author in \cite{Bi23} proved that the generalised pair $(Z,B_Z+M_Z)$ given by the canonical bundle formula is generalised $\delta$-lc where…

Algebraic Geometry · Mathematics 2024-12-13 Caucher Birkar , Bingyi Chen

The Buchsbaum-Eisenbud-Horrocks Conjecture predicts that if M is a non-zero module of finite length and finite projective dimension over a local ring R of dimension d, then the i-th Betti number of M is at least d choose i. This conjecture…

Commutative Algebra · Mathematics 2017-06-06 Mark E. Walker

We produce a formula for the $\mathbb{Z}_2$-Betti numbers of the moduli space $M_r^d$ of stable real Higgs bundles over a real projective curve, with coprime rank $r$ and degree $d$. Our approach relies on the motivic formula for the moduli…

Algebraic Geometry · Mathematics 2026-05-20 Thomas John Baird

Let $\pi\cln X\to \Delta^m$ be a proper smooth K\"ahler morphism from a complex manifold $X$ to the unit polydisc $\Delta^m$. Suppose the fibers over the complement of a proper analytic subset are biholomorphic to a fixed projective…

Algebraic Geometry · Mathematics 2026-05-11 Mu-Lin Li , Xiao-Lei Liu

We prove some general results on syzygies of smooth projective varieties with numerically trivial canonical line bundle. This allows to confirm several cases of Mukai's syzygies conjecture for finite quotients of abelian varieties in any…

Algebraic Geometry · Mathematics 2025-09-22 Federico Caucci

Fujita's second theorem for K\"ahler fibre spaces over a curve asserts that the direct image $V$ of the relative dualizing sheaf splits as the direct sum $ V = A \oplus Q$, where $A$ is ample and $Q$ is unitary flat. We focus on our…

Algebraic Geometry · Mathematics 2016-05-11 Fabrizio Catanese , Michael Dettweiler

We show that principal bundles for a semisimple group on an arbitrary affine curve over an algebraically closed field are trivial, provided the order of $\pi_1$ of the group is invertible in the ground field, or if the curve has semi-normal…

Algebraic Geometry · Mathematics 2017-12-12 Prakash Belkale , Najmuddin Fakhruddin