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In an unpublished preprint, A. King conjectured that there are tilting bundles over projective varieties which are obtained as invariant quotients of affine spaces for linear actions of reductive groups. The goal of this paper is to give…

Algebraic Geometry · Mathematics 2009-06-19 Mihai Halic

Let E and F be vector bundles over a complex projective smooth curve X, and suppose that 0 -> E -> W -> F -> 0 is a nontrivial extension. Let G be a subbundle of F, and D an effective divisor on X. We give a criterion for the subsheaf G(-D)…

Algebraic Geometry · Mathematics 2013-06-11 George H. Hitching

In this paper, we use canonical bundle formulas to prove some generalizations of an old theorem of Kawamata on the semiampleness of nef and abundant log canonical divisors. In particular, we show that for klt pairs $(X,B)$ with $K_X+B$…

Algebraic Geometry · Mathematics 2022-09-07 Priyankur Chaudhuri

Let $X$ be a smooth projective variety over an algebraically closed field $\mathbb{K}$ with arbitrary characteristic. Suppose $L$ is an ample and globally generated line bundle. By Castelnuovo--Mumford regularity, we show that $K_X \otimes…

Algebraic Geometry · Mathematics 2018-04-10 Xiaoyu Su , Xiaokui Yang

We show that curve enumeration invariants of complex threefolds with nef anti-canonical bundle are determined by their values on local curves. This implies the MNOP conjecture of Maulik, Nekrasov, Okounkov, and Pandharipande relating…

Algebraic Geometry · Mathematics 2025-08-27 John Pardon

In this note we study properties of partially ample line bundles on simplicial projective toric varieties. We prove that the cone of q-ample line bundles is a union of rational polyhedral cones, and calculate these cones in examples. We…

Algebraic Geometry · Mathematics 2014-09-29 Nathan Broomhead , John Christian Ottem , Artie Prendergast-Smith

We study the Iitaka-Kodaira dimension of nef relative anti-canonical divisors. As a consequence, we prove that given a complex projective variety with klt singularities, if the anti-canonical divisor is nef, then the dimension of a general…

Algebraic Geometry · Mathematics 2019-07-10 Sho Ejiri , Yoshinori Gongyo

Co lombeau's construction of generalized functions (in its special variant) is extended to a theory of generalized sections of vector bundles. As particular cases, generalized tensor analysis and exterior algebra are studied. A point value…

Functional Analysis · Mathematics 2007-05-23 Michael Kunzinger , Roland Steinbauer

A generalised notion of connection on a fibre bundle E over a manifold M is presented. These connections are characterised by a smooth distribution on E which projects onto a (not necessarily integrable) distribution on M and which, in…

Differential Geometry · Mathematics 2007-05-23 F. Cantrijn , B. Langerock

We prove that any Fano manifold of coindex three admitting nef tangent bundle is homogeneous.

Algebraic Geometry · Mathematics 2019-04-24 Kiwamu Watanabe

We develop a generalized field space geometry for higher-derivative scalar field theories, expressing scattering amplitudes in terms of a covariant geometry on the all-order jet bundle. The incorporation of spacetime and field derivative…

High Energy Physics - Theory · Physics 2024-02-12 Nathaniel Craig , Yu-Tse Lee

Given a complex manifold $X$, any K\"ahler class defines an affine bundle over $X$, and any K\"ahler form in the given class defines a totally real embedding of $X$ into this affine bundle. We formulate conditions under which the affine…

Complex Variables · Mathematics 2020-06-18 Daniel Greb , Michael Lennox Wong

This paper presents a generalization of symplectic geometry to a principal bundle over the configuration space of a classical field. This bundle, the vertically adapted linear frame bundle, is obtained by breaking the symmetry of the full…

dg-ga · Mathematics 2015-06-25 J. K. Lawson

A noncommutative-geometric generalization of the classical formalism of frame bundles is developed, incorporating into the theory of quantum principal bundles the concept of the Levi-Civita connection. The construction of a natural…

q-alg · Mathematics 2008-02-03 Mico Durdevic

The aim of this note is to exhibit explicit sufficient criteria ensuring bigness of globally generated, rank-$r$ vector bundles, $r \geqslant 2$, on smooth, projective varieties of even dimension $d \leqslant 4$. We also discuss connections…

Algebraic Geometry · Mathematics 2019-11-05 Gilberto Bini , Flaminio Flamini

We study non-Kaehler manifolds with trivial logarithmic tangent bundle. We show that each such manifold arises as a fiber bundle with a compact complex parallelizable manifold as basis and a toric variety as fiber.

Complex Variables · Mathematics 2007-05-23 Joerg Winkelmann

In this paper we study holomorphic vector bundles with singular Hermitian metrics whose curvature are Hermitian matrix currents. We obtain an extension theorem for holomorphic jet sections of nef holomorphic vector bundle on compact…

Algebraic Geometry · Mathematics 2014-12-30 Qilin Yang

We prove that a holomorphic line bundle on a projective manifold is pseudo-effective if and only if its degree on any member of a covering family of curves is non-negative. This is a consequence of a duality statement between the cone of…

Algebraic Geometry · Mathematics 2007-05-23 Sébastien Boucksom , Jean-Pierre Demailly , Mihai Paun , Thomas Peternell

We present a smooth, complete toric threefold with no nontrivial nef line bundles. This is a counterexample to a recent conjecture of Fujino.

Algebraic Geometry · Mathematics 2007-05-23 Sam Payne

We review the concept of a graded bundle as a natural generalisation of a vector bundle. Such geometries are particularly nice examples of more general graded manifolds. With hindsight there are many examples of graded bundles that appear…

Differential Geometry · Mathematics 2016-05-12 Andrew J. Bruce , K. Grabowska , J. Grabowski