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We prove that the space of affine, transversal at infinity, non-singular real cubic surfaces has 15 connected components. We give a topological criterion to distinguish them and show also how these 15 components are adjacent to each other…

Algebraic Geometry · Mathematics 2023-01-24 Sergey Finashin , Viatcheslav Kharlamov

In this article we study the deformation of finite maps and show how to use this deformation theory to construct varieties with given invariants in a projective space. Among other things, we prove a criterion that determines when a finite…

Algebraic Geometry · Mathematics 2010-06-08 F. J. Gallego , M. González , B. P. Purnaprajna

We introduce a class of surfaces in euclidean space motivated by a problem posed by \'{E}lie Cartan. This class furnishes what seems to be the first examples of pairs of non-congruent surfaces in euclidean space such that, under a…

Differential Geometry · Mathematics 2014-10-02 Antonio Martínez , Pedro Roitman

We construct the first examples of regular del Pezzo surfaces for which the irregularity (i.e. the dimension of the first cohomology group of the structure sheaf) is nonzero. We also find a restriction on the integer pairs that are possible…

Algebraic Geometry · Mathematics 2013-04-23 Zachary Maddock

We introduce a characterization for affine equivalence of two surfaces of translation defined by either rational or meromorphic generators. In turn, this induces a similar characterization for minimal surfaces. In the rational case, our…

Algebraic Geometry · Mathematics 2021-12-20 Juan Gerardo Alcázar , Georg Muntingh

We show that two smoothly bounded, strongly pseudoconvex domains which are diffeomorphic may be smoothly deformed into each other, with all intermediate domains being strongly pseudoconvex. This result relates to Lempert's ideas about…

Complex Variables · Mathematics 2010-04-22 Steven G. Krantz

In this paper, we give a finiteness result on the diffeomorphism types of curvature-adapted equifocal hypersurfaces in a simply connected compact symmetric space. Furthermore, the condition curvature-adapted can be dropped if the symmetric…

Differential Geometry · Mathematics 2012-01-11 Jianquan Ge , Chao Qian , Zizhou Tang

In Dubouloz and Mangolte (Fake real planes: exotic affine algebraic models of $\mathbb{R}^{2}$, arXiv:1507.01574, 2015) we define and partially classify fake real planes, that is, minimal complex surfaces with conjugation whose real locus…

Algebraic Geometry · Mathematics 2022-06-22 Adrien Dubouloz , Frédéric Mangolte

We show that a minimal surface of general type has a canonical symplectic structure (unique up to symplectomorphism) which is invariant for smooth deformation. We show that the symplectomorphism type is also invariant for deformations which…

Algebraic Geometry · Mathematics 2007-05-23 Fabrizio Catanese

We study automorphism groups of real del Pezzo surfaces, concentrating on finite groups acting minimally on them. As a result, we obtain a vast part of classification of finite subgroups in the real plane Cremona group.

Algebraic Geometry · Mathematics 2021-12-14 Egor Yasinsky

In this paper we study Moebius applicable surfaces, i.e., conformally immersed surfaces in Moebius 3-space which admit deformations preserving the Moebius metric. We show new characterizations of Willmore surfaces, Bonnet surfaces and…

Differential Geometry · Mathematics 2007-05-23 Atsushi Fujioka , Jun-ichi Inoguchi

We study surjective (not necessarily regular) rational endomorphisms $f$ of smooth del Pezzo surfaces $X$. We prove that under certain natural non\,-\,degeneracy condition $f$ can have degree bigger than $1$ only when $(-K_X^2) > 5$. Some…

Algebraic Geometry · Mathematics 2025-06-03 Ilya Karzhemanov , Anna Lekontseva

We study complex plane projective sextic curves with simple singularities up to equisingular deformations. It is shown that two such curves are deformation equivalent if and only if the corresponding pairs are diffeomorphic. A way to…

Algebraic Geometry · Mathematics 2008-03-21 Alex Degtyarev

We introduce a new invariant, the real (logarithmic)-Kodaira dimension, that allows to distinguish smooth real algebraic surfaces up to birational diffeomorphism. As an application, we construct infinite families of smooth rational real…

Algebraic Geometry · Mathematics 2023-06-22 Jérémy Blanc , Adrien Dubouloz

We establish a couple of dynamical properties of surjective rational maps $f: X \dashrightarrow X$ for smooth projective surfaces $X$. We also give a numerical characterization of regular $f$ in the case when $X$ is a del Pezzo surface.…

Algebraic Geometry · Mathematics 2026-03-26 Ilya Karzhemanov

By an exotic algebraic structure on the affine space ${\bf C}^n$ we mean a smooth affine algebraic variety which is diffeomorphic to ${\bf R}^{2n}$ but not isomorphic to ${\bf C}^n$. This is a survey of the recent developement on the…

alg-geom · Mathematics 2008-02-03 Mikhail Zaidenberg

We study infinitesimal conformal deformations of a triangulated surface in Euclidean space and investigate the change in its extrinsic geometry. A deformation of vertices is conformal if it preserves length cross-ratios. On one hand,…

Metric Geometry · Mathematics 2018-04-19 Wai Yeung Lam , Ulrich Pinkall

We prove a Diophantine approximation inequality for closed subschemes on surfaces which can be viewed as a joint generalization of recent inequalities of Ru-Vojta and Heier-Levin in this context. As applications, we study various…

Number Theory · Mathematics 2024-06-28 Keping Huang , Aaron Levin , Zheng Xiao

We classify smooth del Pezzo surfaces whose alpha-invariant of Tian is bigger than one.

Algebraic Geometry · Mathematics 2011-01-12 Ivan Cheltsov , Andrew Wilson

In this paper we study the deformation of strictly convex real projective structures on a closed surface. Specially we study the deformation in terms of the entropy on bulging deformations. As a byproduct we construct a sequence of…

Geometric Topology · Mathematics 2016-11-01 Patrick Foulon , Inkang Kim