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A mixed type surface is a connected regular surface in a Lorentzian 3-manifold with non-empty spacelike and timelike point sets. The induced metric of a mixed type surface is a signature-changing metric, and their lightlike points may be…

Differential Geometry · Mathematics 2019-11-26 Atsufumi Honda , Kentaro Saji , Keisuke Teramoto

The degree of irrationality of a smooth projective variety $X$ is the minimal degree of a dominant rational map $X\dashrightarrow \mathbb{P}^{\dim X}$. We show that if an abelian surface $A$ over $\mathbb{C}$ is such that the image of the…

Algebraic Geometry · Mathematics 2019-11-04 Olivier Martin

Let $X$ be an irreducible projective variety of dimension $n$ in a projective space and let $x$ be a point of $X$. Denote by ${\rm Curves}_d(X,x)$ the space of curves of degree $d$ lying on $X$ and passing through $x$. We will show that the…

Algebraic Geometry · Mathematics 2007-05-23 Jun-Muk Hwang

The main result of the paper is a boundedness for $n$-complements on algebraic surfaces. In addition, applications of this theorem to a classification of log Del Pezzo surfaces and of birational contractions for 3-folds are formulated.

alg-geom · Mathematics 2007-05-23 V. V. Shokurov

We give two generalizations of the Clifford theorem to algebraic surfaces. As an application, we obtain some bounds for the number of moduli of surfaces of general type.

Algebraic Geometry · Mathematics 2013-01-08 Hao Sun

We give explicit isoperimetric upper bounds for all Steklov eigenvalues of a compact orientable surface with boundary, in terms of the genus, the length of the boundary, and the number of boundary components. Our estimates generalize a…

Spectral Theory · Mathematics 2013-10-10 Alexandre Girouard , Iosif Polterovich

In this paper, we define a new type of ruled surface called ruled surface by using the alternative frame of a base curve. Then, we study its differential geometric properties such as striction line, distribution parameter, fundamental…

Differential Geometry · Mathematics 2019-10-16 Burak Sahiner

We develop a new method for proving explicit approximation lower bounds for TSP problems with bounded metrics improving on the best up to now known bounds. They almost match the best known bounds for unbounded metric TSP problems. In…

Computational Complexity · Computer Science 2012-08-09 Marek Karpinski , Richard Schmied

We give an a priori bound on the (n-7)-dimensional measure of the singular set for an area-minimizing n-dimensional hypersurface, in terms of the geometry of its boundary.

Differential Geometry · Mathematics 2019-01-10 Nick Edelen

Let U be the complement of a smooth anticanonical divisor in a del Pezzo surface of degree at most 7 over a number field k. We show that there is an effective uniform bound for the size of the Brauer group of U in terms of the degree of k.

Algebraic Geometry · Mathematics 2019-03-06 Martin Bright , Julian Lyczak

We consider elliptic surfaces $\mathcal{E}$ over a field $k$ equipped with zero section $O$ and another section $P$ of infinite order. If $k$ has characteristic zero, we show there are only finitely many points where $O$ is tangent to a…

Algebraic Geometry · Mathematics 2020-10-21 Douglas Ulmer , Giancarlo Urzúa

We present a computational scheme that derives a global polynomial level set parametrisation for smooth closed surfaces from a regular surface-point set and prove its uniqueness. This enables us to approximate a broad class of smooth…

New historical aspects of the classification, by Cayley and Cremona, of ruled quartic surfaces and the relation to string models and plaster models are presented. In a `modern' treatment of the classification of ruled quartic surfaces the…

Algebraic Geometry · Mathematics 2009-04-16 Irene Polo-Blanco , Marius van der Put , Jaap Top

In this article we prove the global existence of a unique strong solution to the initial boundary-value problem for a fourth-order exponential PDE. The equation we study was originally proposed to study the evolution of crystal surfaces,…

Analysis of PDEs · Mathematics 2022-06-29 Brock C. Price , Xiangsheng Xu

We prove a lower bound for the first Steklov eigenvalue of embedded minimal hypersurfaces with free boundary in a compact $n$-dimensional manifold which has nonnegative Ricci curvature and strictly convex boundary. When $n=3$, this implies…

Differential Geometry · Mathematics 2020-01-06 Ailana Fraser , Martin Li

In this article we apply the classical method of focal loci of families to give a lower bound for the genus of curves lying on general surfaces. First we translate and reprove Xu's result that any curve C on a general surface in P^3 of…

Algebraic Geometry · Mathematics 2007-05-23 L. Chiantini , A. F. Lopez

In the present paper, we provide general bounds for the torsion in the codimension 2 Chow groups of the products of projective homogeneous surfaces. In particular, we determine the torsion for the product of four Pfister quadric surfaces…

Algebraic Geometry · Mathematics 2015-11-13 Sanghoon Baek

We prove lower bounds for the minimum distance of algebraic geometry codes over surfaces whose canonical divisor is either nef or anti-strictly nef and over surfaces without irreducible curves of small genus. We sharpen these lower bounds…

Algebraic Geometry · Mathematics 2020-03-04 Yves Aubry , Elena Berardini , Fabien Herbaut , Marc Perret

A proof for the lower bound is provided for the smallest eigenvalue of finite element equations with arbitrary conforming simplicial meshes. The bound has a similar form as the one by Graham and McLean [SIAM J. Numer. Anal., 44 (2006), pp.…

Numerical Analysis · Mathematics 2021-06-24 Lennard Kamenski

In this paper, based on the theory of surfaces in the four-dimensional Euclidean space which generalizes the theory of surfaces in three-dimensional Euclidean space, beside other results, we will give a characterization of points on…

Differential Geometry · Mathematics 2013-10-24 Azam Etemad Dehkordy