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Let $X$ be a cubic fourfold that has only simple singularities and does not contain a plane. We prove that the Fano variety of lines on $X$ has the same analytic type of singularity as the Hilbert scheme of two points on a surface with only…

Algebraic Geometry · Mathematics 2018-04-03 Ryo Yamagishi

After introducing the different boundary geometries of rank one symmetric spaces, we state and prove Fried's theorem in the general setting of all those geometries: a closed manifold with a similarity structure is either complete or the…

Differential Geometry · Mathematics 2019-09-25 Raphaël Alexandre

We generalize the Guth--Katz joints theorem from lines to varieties. A special case says that $N$ planes (2-flats) in 6 dimensions (over any field) have $O(N^{3/2})$ joints, where a joint is a point contained in a triple of these planes not…

Combinatorics · Mathematics 2022-06-03 Jonathan Tidor , Hung-Hsun Hans Yu , Yufei Zhao

We prove well posedness and stability in $\mathbf{L}^1$ for a class of mixed hyperbolic-parabolic non linear and non local equations in a bounded domain with no flow along the boundary. While the treatment of boundary conditions for the…

Analysis of PDEs · Mathematics 2025-02-17 Rinaldo M. Colombo , Elena Rossi , Abraham Sylla

We consider the Fano scheme $F_k(X)$ of $k$--dimensional linear subspaces contained in a complete intersection $X \subset \mathbb{P}^n$ of multi--degree $\underline{d} = (d_1, \ldots, d_s)$. Our main result is an extension of a result of…

Algebraic Geometry · Mathematics 2020-09-30 F. Bastianelli , C. Ciliberto , F. Flamini , P. Supino

We prove sharp $L^2$ Fourier restriction inequalities for compact, smooth surfaces in $\mathbb{R}^3$ equipped with the affine surface measure or a power thereof. The results are valid for all smooth surfaces and the bounds are uniform for…

Classical Analysis and ODEs · Mathematics 2024-11-08 Jianhui Li

In this paper the log surfaces without $\QQ$-complement are classified. In particular, they are non-rational always. This result takes off the restriction in the theory of complements and allows one to apply it in the most wide class of log…

Algebraic Geometry · Mathematics 2007-05-23 I. Yu. Fedorov , S. A. Kudryavtsev

This paper gives sharp linear bounds on the genus of a normal surface in a triangulated compact, orientable 3--manifold in terms of the quadrilaterals in its cell decomposition---different bounds arise from varying hypotheses on the surface…

Geometric Topology · Mathematics 2016-07-20 William Jaco , Jesse Johnson , Jonathan Spreer , Stephan Tillmann

It is proved that a generic simple, closed, piecewise regular curve in space can be the boundary of only finitely many developable surfaces with nonvanishing mean curvature. The relevance of this result in the context of the dynamics of…

Differential Geometry · Mathematics 2021-03-03 Maria Alberich-Carramiñana , Jaume Amorós , Franco Coltraro

We treat the boundary problem for complex varieties (with isolated singularities) of dimension greater than one, which are contained in a suitable class of strictly pseudoconvex, unbounded domains of C^n.

Complex Variables · Mathematics 2007-05-23 Giuseppe Della Sala , Alberto Saracco

We study the homeomorphism types of certain covers of (always orientable) surfaces, usually of infinite-type. We show that every surface with non-abelian fundamental group is covered by every noncompact surface, we identify the universal…

Geometric Topology · Mathematics 2025-08-05 Ian Biringer , Yassin Chandran , Tommaso Cremaschi , Jing Tao , Nicholas G. Vlamis , Mujie Wang , Brandis Whitfield

In this article we prove the following boundedness result: Fix a DCC set $I\subset [0, 1]$. Let $\mathfrak{D}$ be the set of all log pairs $(X, \Delta)$ satisfying the following properties: (i) $X$ is a projective surface defined over an…

Algebraic Geometry · Mathematics 2020-11-10 Omprokash Das

Arrondo, Sols and De Cataldo proved that there are only finitely many families of codimension two subvarieties not of general type in the smooth quadric of dimension $n+2$ for $n\ge 2 $, $n\neq 4$. In this paper we drop the assumption…

alg-geom · Mathematics 2008-02-03 Lucia Fania , Giorgio Ottaviani

We prove that a general complete intersection of dimension $n$, codimension $c$ and type $d_1, \dots, d_c$ in $\mathbb{P}^N$ has ample cotangent bundle if $c \geq 2n-2$ and the $d_i$'s are all greater than a bound that is $O(1)$ in $N$ and…

Algebraic Geometry · Mathematics 2020-02-05 Izzet Coskun , Eric Riedl

The aim of this paper is to prove a uniform Fourier restriction estimate for certain $2-$dimensional surfaces in $\mathbb R^{2n}$. These surfaces are the image of complex polynomial curves $\gamma(z) = (p_1(z), \dots, p_n(z))$, equipped…

Classical Analysis and ODEs · Mathematics 2020-04-01 Jaume de Dios Pont

Given an elliptic surface $\mathcal{E}\to\mathcal{C}$ over a field $k$ of characteristic zero equipped with zero section $O$ and another section $P$ of infinite order, we give a simple and explicit upper bound on the number of points where…

Algebraic Geometry · Mathematics 2020-05-27 Douglas Ulmer , Giancarlo Urzúa

In this paper we give a geometric argument for bounding the diameter of a connected compact surface (with boundary) of arbitrary codimension in Euclidean space in terms of Topping's diameter bound for closed surfaces (without boundary). The…

Differential Geometry · Mathematics 2023-01-11 Tatsuya Miura

We provide an infinite family of diffeomorphic symplectic forms on ruled surfaces, which are pairwise non-isotopic. This answers a uniqueness question regarding symplectic structures up to isotopy on closed symplectic four-manifolds.

Symplectic Geometry · Mathematics 2025-07-23 Jianfeng Lin , Weiwei Wu

In this note we propose a min-max theory for embedded hypersurfaces with a fixed boundary and apply it to prove several theorems about the existence of embedded minimal hypersurfaces with a given boundary. A simpler variant of these…

Analysis of PDEs · Mathematics 2017-05-19 Camillo De Lellis , Jusuf Ramic

We show the abundance theorem for arithmetic klt threefold pairs whose closed point have residue characteristic greater than five. As a consequence, we give a sufficient condition for the asymptotic invariance of plurigenera for certain…

Algebraic Geometry · Mathematics 2022-11-24 Fabio Bernasconi , Iacopo Brivio , Liam Stigant