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We study and obtain Slope inequalities for fibred irregular varieties of non-maximal Albanese dimension. We give a comparison theorem between Clifford-Severi and Slope inequalities for this type of fibrations. We also obtain a set of Slope…

Algebraic Geometry · Mathematics 2020-12-29 Miguel A. Barja

Let f:S ->B be a relatively minimal fibred surface. In this note we give a partial affirmative answer to a conjecture of Xiao, proving that the direct image of the relative dualizing sheaf of $f$ is ample when the slope of the fibration is…

Algebraic Geometry · Mathematics 2007-05-23 Miguel A. Barja , Francesco Zucconi

The \textit{slope} of a fibered $3$-folds $f:X \to B$ is a relative numerical invariant defined by $\lambda(f) := K_{f}^{3}/\mathrm{deg}(f_{\ast}\omega_{f})$, where $K_{f}$ is the relative canonical divisor and $\omega_{f}$ is the relative…

Algebraic Geometry · Mathematics 2024-04-09 Hiroto Akaike

We give lower bounds for the slope of higher dimensional fibrations over curves under conditions of GIT-semistability of the fibres, using a generalization of a method of Cornalba and Harris. With the same method we establish a sharp lower…

Algebraic Geometry · Mathematics 2023-12-29 Miguel A. Barja , Lidia Stoppino

We show various properties of smooth projective D-affine varieties. In particular, any smooth projective D-affine variety is algebraically simply connected and its image under a fibration is D-affine. In characteristic zero such D-affine…

Algebraic Geometry · Mathematics 2023-01-31 Adrian Langer

In this note, we extend work of Farkas and Rim\'anyi on applying quadric rank loci to finding divisors of small slope on the moduli space of curves by instead considering all divisorial conditions on the hypersurfaces of a fixed degree…

Algebraic Geometry · Mathematics 2021-10-06 Dennis Tseng

Given a connected smooth projective surface X over the complex numbers, together with a simple normal crossings divisor D on it, we study finite normal covers Y of X that are unramified outside D. Given moreover a fibration of X onto a…

Algebraic Geometry · Mathematics 2012-03-28 Bas Edixhoven , Robin de Jong , Jan Schepers

For a general $k$-gonal curve $C$ with a morphism $f: C \rightarrow \mathbb{P}^1$ of degree $k$, we consider the refinement of the Brill-Noether schemes $W^r_d(C)$ by means of the Brill-Noether degeneracy schemes…

Algebraic Geometry · Mathematics 2026-03-25 Marc Coppens

Given cell-average data values of a piecewise smooth bivariate function $f$ within a domain $\Omega$, we look for a piecewise adaptive approximation to $f$. We are interested in an explicit and global (smooth) approach. Bivariate…

Numerical Analysis · Mathematics 2022-01-27 Sergio Amat , David Levin , Juan Ruiz-Alvarez , Dionisio F. Yáñez

In a previous joint article with F. Abu Salem, we gave efficient algorithms for Jacobian group arithmetic of "typical" divisor classes on C_{3,4} curves, improving on similar results by other authors. At that time, we could only state that…

Number Theory · Mathematics 2019-08-08 Kamal Khuri-Makdisi

Let $f: X \to Y$ be a dominant morphism of smooth, proper and geometrically integral varieties over a number field $k$, with geometrically integral generic fibre. We give a necessary and sufficient geometric criterion for the induced map…

Algebraic Geometry · Mathematics 2018-09-28 Daniel Loughran , Alexei N. Skorobogatov , Arne Smeets

We prove the equivalence between Clifford-Severi inequalities for good classes of varieties of maximal Albanese dimension and Slope Inequalities for fibrations of such varieties over curves. This provides a big set of new Slope Inequalities…

Algebraic Geometry · Mathematics 2020-12-29 Miguel A. Barja

I prove new local inequality for divisors on smooth surfaces, describe its applications, and compare it to a similar local inequality that is already known by experts.

Algebraic Geometry · Mathematics 2013-11-22 Ivan Cheltsov

We make a very detailed analysis of the numerical properties of effective divisors whose support is contained in the exceptional locus of a birational morphism of smooth projective surfaces. As an application we extend Miyaoka's inequality…

Algebraic Geometry · Mathematics 2022-07-19 Vicente Lorenzo , Margarida Mendes Lopes , Rita Pardini

We prove effective upper bounds on the global sections of nef line bundles of small generic degree over a fibered surface over a field of any characteristic. It can be viewed as a relative version of the classical Noether inequality for…

Algebraic Geometry · Mathematics 2013-04-24 Xinyi Yuan , Tong Zhang

We study slopes of finite cyclic covering fibrations of a fibered surface. We give the best possible lower bound of the slope of these fibrations. We also give the slope equality of finite cyclic covering fibrations of a ruled surface and…

Algebraic Geometry · Mathematics 2016-04-19 Makoto Enokizono

In this note we address the following kind of question: let X be a smooth, irreducible, projective surface and D a divisor on X$satisfying some sort of positivity hypothesis, then is there some multiple of D depending only on X which is…

For a proper, flat, generically smooth scheme $X$ over a complete DVR with finite residue field of characteristic $p$, we define a specialization morphism from the rigid cohomology of the geometric special fibre to $D_{crys}$ of the…

Algebraic Geometry · Mathematics 2015-12-01 Yi-Tao Wu

For a function $f$ on the hypercube $\{0,1\}^n$ with Fourier expansion $f=\sum_{S\subseteq[n]}\hat f(S)\chi_S$, the hypercontractive inequality allows bounding norms of $T_\rho f=\sum_S\rho^{|S|} \hat f(S)\chi_S$ in terms of norms of $f$.…

Combinatorics · Mathematics 2025-11-26 Nathan Keller , Noam Lifshitz , Omri Marcus

We extend Wolff's "local smoothing" inequality to a wider class of not necessarily conical hypersurfaces of codimension 1. This class includes surfaces with nonvanishing curvature, as well as certain surfaces with more than one flat…

Classical Analysis and ODEs · Mathematics 2007-05-23 Izabella Laba , Malabika Pramanik