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Related papers: Real structures on minimal ruled surfaces

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This is the first of a series of papers studying real algebraic threefolds using the minimal model program. The main results are outlined in Part II. The present part I. contains the necessary preliminary work concerning terminal…

alg-geom · Mathematics 2007-05-23 János Kollár

In this paper we consider flat metrics (semi-translation structures) on surfaces of finite type. There are two main results. The first is a complete description of when a set of simple closed curves is spectrally rigid, that is, when the…

Geometric Topology · Mathematics 2015-05-13 Moon Duchin , Christopher J. Leininger , Kasra Rafi

In many cases rational surfaces obtained by desingularization of birational dynamical systems are not relatively minimal. We propose a method to obtain coordinates of relatively minimal rational surfaces by using blowing down structure. We…

Dynamical Systems · Mathematics 2013-04-09 Adrian Stefan Carstea , Tomoyuki Takenawa

We investigate the existence of minimal hypersurfaces in $\mathbb{S}^{n+1}$ that are generated by the isoparametric foliation of a subsphere $\mathbb{S}^n$. By considering a generalized rotational ansatz formed by the union of homothetic…

Differential Geometry · Mathematics 2026-03-05 Junqi Lai , Guoxin Wei

In this paper, we study some relationships existing between some particular mathematical structures: discrete surfaces coming from discrete topology and mathematical morphology, poset-based connected manifolds coming from discrete topology,…

Algebraic Topology · Mathematics 2025-08-05 Nicolas Boutry

We study ruled real hypersurfaces whose shape operators have constant squared norm in nonflat complex space forms. In particular, we prove the nonexistence of such hypersurfaces in the projective case. We also show that biharmonic ruled…

Differential Geometry · Mathematics 2020-02-06 Olga Perez-Barral

We classify minimal sets of (closed and oriented) hyperbolic surface homeomorphisms by studying the connected components of their complement. This extends the classification given by F. Kwakkel, T.J\"ager and A. Passeggi in the torus. The…

Dynamical Systems · Mathematics 2012-08-21 Alejandro Passeggi , Juliana Xavier

It is well-known that in any codimension a simply connected Euclidean minimal surface has an associated one-parameter family of minimal isometric deformations. In this paper, we show that this is just a special case of the associated family…

Differential Geometry · Mathematics 2015-02-17 Marcos Dajczer , Theodoros Vlachos

The study of topological information of spatial objects has for a long time been a focus of research in disciplines like computational geometry, spatial reasoning, cognitive science, and robotics. While the majority of these researches…

Artificial Intelligence · Computer Science 2015-03-13 Sanjiang Li

I have finalized my old (1979) results about enumeration of connected components of moduli of real polarized K3 surfaces. As an application, using recent results of math.AG/0312396, the complete classification of real polarized K3 surfaces…

Algebraic Geometry · Mathematics 2009-12-08 Viacheslav V. Nikulin

We present a diagram surveying equivalence or strict implication for properties of different nature (algebraic, model theoretic, topological, etc.) about groups definable in o-minimal structures. All results are well-known and an extensive…

Logic · Mathematics 2020-10-29 Annalisa Conversano

It is pointed out that despite of the non-linearity of the underlying equations, there do exist rather general methods that allow to generate new minimal surfaces from known ones.

Differential Geometry · Mathematics 2018-11-26 Jens Hoppe , Vladimir G. Tkachev

We apply the complex analysis over the double numbers $D$ to study the minimal time-like surfaces in $R^4_2$. A minimal time-like surface which is free of degenerate points is said to be of general type. We divide the minimal time-like…

Differential Geometry · Mathematics 2019-12-03 Georgi Ganchev , Krasimir Kanchev

Deformation theory is treated for locally notherian formal schemes (non necessarily smooth). The cotangent complex is defined in the derived category through the homology localization functor. The basic properties and results of a…

Algebraic Geometry · Mathematics 2024-02-06 Marta Pérez Rodríguez

After introducing some motivations for this survey, we describe a formalism to parametrize a wide class of algebraic structures occurring naturally in various problems of topology, geometry and mathematical physics. This allows us to define…

Algebraic Topology · Mathematics 2016-12-16 Sinan Yalin

In this expository paper, we first review the classification of the restricted simple Lie algebras in characteristic different from 2 and 3 and then we describe their infinitesimal deformations. We conclude by indicating some possible…

Rings and Algebras · Mathematics 2014-01-06 Filippo Viviani

We classify webs of minimal degree rational curves on surfaces and give a criterion for webs being hexagonal. In addition, we classify Neron-Severi lattices of real weak del Pezzo surfaces. These two classifications are related to root…

Algebraic Geometry · Mathematics 2021-03-09 Niels Lubbes

We generalise a result of Garofalo and Pauls: a horizontally minimal smooth surface embedded in the Heisenberg group is locally a (straight) ruled surface, i.e. it consists of straight lines tangent to a horizontal vector field along a…

Differential Geometry · Mathematics 2014-01-30 Ioannis D. Platis

The aim of this paper is to present the main constructions of the substructures of an almost groupoid and to discuss their basic properties. The definitions and properties concerning these new algebraic constructions extend to almost…

Group Theory · Mathematics 2026-02-06 Mihai Ivan

A behavior of extreme networks under deformations of their boundary sets is investigated. It is shown that analyticity of a deformation of boundary set guarantees preservation of the networks types for minimal spanning trees, minimal…

Differential Geometry · Mathematics 2015-06-24 Alexander Ivanov , Alexey Tuzhilin