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Related papers: Effective base point freeness on normal surfaces

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This treats the base-point-freeness of the adjoint bundles on normal surfaces with a boundary. This is an extension of the non-relative version of the theorem of Ein-Lazarsfeld-Masek and the theorem of Kawachi-Masek.

alg-geom · Mathematics 2008-02-03 Takeshi Kawachi

We extend Reider's freeness criterion to normal surfaces of characteristic 0. Let Y be a normal surface. Let D be a nef divisor on Y such that K_Y+D is a Cartier divisor. Let x be a point on Y. If x is a base point of |K_Y+D| and…

alg-geom · Mathematics 2008-02-03 Takeshi Kawachi

In this note we establish a new Fujita-type effective bound for the base point freeness of adjoint line bundles on a compact complex projective manifold of complex dimension $n$. The bound we obtain (approximately) differs from the linear…

Algebraic Geometry · Mathematics 2007-05-23 Gordon Heier

We reformulate base point free theorems. Our formulation is flexible and has some important applications. One of the main purposes of this paper is to prove a generalization of the base point free theorem in Fukuda's paper: On numerically…

Algebraic Geometry · Mathematics 2011-02-18 Osamu Fujino

We obtain effective results for the global generation of pluritheta line bundles on moduli spaces of vector bundles on curves. The main ingredient is an independent result giving an upper bound on the dimension of the Hilbert scheme of…

Algebraic Geometry · Mathematics 2007-05-23 Mihnea Popa

We give effective bounds on the generation of pushforwards of log-pluricanonical bundles twisted by ample line bundles. This gives a partial answer to a conjecture proposed by Popa and Schnell. We prove two types of statements: first, more…

Algebraic Geometry · Mathematics 2018-10-30 Yajnaseni Dutta

We prove a Fujita-type theorem for varieties with numerically trivial canonical bundle using properties of semihomogeneous bundles on abelian varieties. We combine our results with work of Riess on compact hyperk\"{a}hler manifolds and work…

Algebraic Geometry · Mathematics 2022-03-08 Alex Küronya , Yusuf Mustopa

We prove a gluing theorem which allows to construct an ample divisor on a rational surface from two given ample divisors on simpler surfaces. This theorem combined with the Cremona action on the ample cone gives rise to an algorithm for…

alg-geom · Mathematics 2008-02-03 Paul Biran

We study the Fujita-type conjecture proposed by Popa and Schnell. We obtain an effective bound on the global generation of direct images of pluri-adjoint line bundles on the regular locus. We also obtain an effective bound on the generic…

Algebraic Geometry · Mathematics 2019-02-07 Masataka Iwai

In \cite{NNM} the author with A. N\'emethi computed the multiplicity of generic surface singularities, the formula is purely topological computable from the resolution graph of the surface singularity. In the present paper we extend the…

Algebraic Geometry · Mathematics 2021-12-30 János Nagy

We explore the birational structure and invariants of a foliated surface $(X, \mathcal F)$ in terms of the adjoint divisor $K_{\mathcal F}+\epsilon K_X$, $0< \epsilon \ll 1$. We then establish a bound on the automorphism group of an adjoint…

Algebraic Geometry · Mathematics 2026-04-17 Calum Spicer , Roberto Svaldi

We construct models of involution surface bundles over algebraic surfaces, degenerating over normal crossing divisors, and with controlled singularities of the total space.

Algebraic Geometry · Mathematics 2018-07-05 Andrew Kresch , Yuri Tschinkel

Let M be a Q-divisor on a smooth surface over C. In this paper we give criteria for very ampleness of the adjoint of the round-up of M. (Similar results for global generation were given by Ein and Lazarsfeld and used in their proof of…

alg-geom · Mathematics 2016-08-30 Vladimir Masek

We give a novel and effective criterion for algebraicity of rational normal analytic surfaces constructed from resolving the singularity of an irreducible curve-germ on $CP^2$ and contracting the strict transform of a given line and all but…

Algebraic Geometry · Mathematics 2012-11-20 Pinaki Mondal

We prove new results on projective normality, normal presentation and higher syzygies for a surface of general type $X$ embedded by adjoint line bundles $L_r = K + rB$, where $B$ is a base point free, ample line bundle. Our main results…

Algebraic Geometry · Mathematics 2012-12-14 P. Banagere , Krishna Hanumanthu

We observe that the proof of the Bogomolov stable restriction theorem can be adapted to give an ampleness criterion for globally generated rank 2 vector bundles on certain surfaces. This applies to the Lazarsfeld-Mukai bundles, to…

Algebraic Geometry · Mathematics 2018-06-04 Arnaud Beauville

We describe a bound on the degree of the generators for some adjoint rings on surfaces and threefolds.

Algebraic Geometry · Mathematics 2018-06-20 Paolo Cascini , De-Qi Zhang

We study the analytic and topological invariants associated with complex normal surface singularities. Our goal is to provide topological formulae for several discrete analytic invariants whenever the analytic structure is generic (with…

Algebraic Geometry · Mathematics 2019-09-17 János Nagy , András Némethi

In [31,32,33] the Gauss-Bonnet formulas for coherent tangent bundles over compact oriented surfaces (without boundary) were proved. We establish the Gauss-Bonnet theorem for coherent tangent bundles over compact oriented surfaces with…

Differential Geometry · Mathematics 2020-05-12 Wojciech Domitrz , Michał Zwierzyński

The set of volumes of stable surfaces does have accumulation points. In this paper, we study this phenomenon for surfaces with one cyclic quotient singularity, towards answering the question under which conditions we can still have…

Algebraic Geometry · Mathematics 2021-07-06 Diana Torres
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