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Related papers: Commensurability Classes of Fake Quadrics

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In the present article, we provide examples of fake quadrics, that is, minimal complex surfaces of general type with the same numerical invariants as the smooth quadric in $\PP ^3$ which are quotients of the bidisc by an irreducible lattice…

Algebraic Geometry · Mathematics 2013-05-23 Amir Džambić

A fake quadric is a smooth minimal surface of general type with the same invariants as the quadric in P^3, i.e. K^2=2c_2=8 and q=p_g=0. We study here quaternionic fake quadrics i.e. fake quadrics constructed arithmetically by using some…

Algebraic Geometry · Mathematics 2016-01-20 Amir Dzambic , Xavier Roulleau

In this paper, we give a criterion to assess the effectiveness and ampleness of divisors on a fake quadric surface $S$, and then we establish a relationship between the cones: \[\mathring{\Eff}(S)=\Amp(S)\subset \SAmp(S)=\Mov(S) \subset…

Algebraic Geometry · Mathematics 2025-03-21 Jianqiang Yang

Generic polyhedra are interesting mathematical objects to study in their own right. In this paper, we initialize a systematic study of two-dimensional generic polyhedra with an eye towards applications to low-dimensional topology,…

Geometric Topology · Mathematics 2026-01-09 Lucas Fagan , Yang Qiu , Zhenghan Wang

We show the existence of odd fake $\mathbb{Q}$-homology quadrics, namely of minimal surfaces $S$ of general type which have the same $\mathbb{Q}$-homology as a smooth quadric $Q \cong (\mathbb{P}^1(\mathbb{C}))^2$, but have an odd…

Algebraic Geometry · Mathematics 2025-08-26 Fabrizio Catanese

We classify rational, irreducible quartic symmetroids in projective 3-space. They are either singular along a line or a smooth conic section, or they have a triple point or a tacnode.

Algebraic Geometry · Mathematics 2017-08-15 Martin Helsø

In our previous works we have classified real non-singular cubic hypersurfaces in the 5-dimensional projective space up to equivalence that includes both real projective transformations and continuous variations of coefficients preserving…

Algebraic Geometry · Mathematics 2020-03-10 Sergey Finashin , Viatcheslav Kharlamov

We give a criterion for certain generic nondegenerate surfaces in a fake weighted projective $3$-space to have Picard number $>1$. These algebraic surfaces are of general type. We do this by considering degenerations (along an edge),…

Algebraic Geometry · Mathematics 2026-04-29 Julius Giesler

A fake projective plane is a smooth complex surface which is not the complex projective plane but has the same Betti numbers as the complex projective plane. The first example of such a surface was constructed by David Mumford in 1979 using…

Algebraic Geometry · Mathematics 2019-03-07 Gopal Prasad , Sai-Kee Yeung

We prove analogues of several well-known results concerning rational morphisms between quadrics for the class of so-called quasilinear $p$-hypersurfaces. These hypersurfaces are nowhere smooth over the base field, so many of the geometric…

Algebraic Geometry · Mathematics 2013-11-19 Stephen Scully

We show that Shavel type surfaces are fake quadrics of even type which are not Mori dream surfaces, yet there are infinitely many primes $p$ such that the reduction modulo $p$ is a Mori dream surface. We investigate fake quadrics, first…

Algebraic Geometry · Mathematics 2025-09-24 Paolo Cascini , Fabrizio Catanese , Yifan Chen , Jong Hae Keum

This paper initiates a systematic study of the relation of commensurability of surface automorphisms, or equivalently, fibered commensurability of 3-manifolds fibering over the circle. We show that every hyperbolic fibered commensurability…

Geometric Topology · Mathematics 2011-04-04 Danny Calegari , Hongbin Sun , Shicheng Wang

We give a criterion for a projective surface to become a quotient of a fake projective plane. We also give a detailed information on the elliptic fibration of a $(2,3)$-elliptic surface that is the minimal resolution of a quotient of a fake…

Algebraic Geometry · Mathematics 2010-10-19 JongHae Keum

There are six orientable, compact, flat 3-manifolds that can occur as cusp cross-sections of hyperbolic 4-manifolds. This paper provides criteria for exactly when a given commensurability class of arithmetic hyperbolic 4-manifolds contains…

Geometric Topology · Mathematics 2023-11-15 Connor Sell

Fake projective planes are smooth complex surfaces of general type with Betti numbers equal to those of the usual projective plane. They come in complex conjugate pairs and have been classified as quotients of the two-dimensional ball by…

Algebraic Geometry · Mathematics 2020-12-16 Lev A. Borisov , JongHae Keum

We define a signed count of real rational pseudo-holomorphic curves appearing in a one-parameter family of real Spin symplectic K3 surfaces. We show that this count is an invariant of the deformation class of the family. In the case of a…

Symplectic Geometry · Mathematics 2015-04-17 Crétois Rémi

First steps towards a classification of irreducible symplectic 4-folds whose integral 2-cohomology with 4-tuple cup product is isomorphic to that of Hilb^2(K3). We prove that any such 4-fold deforms to an irreducible symplectic 4-fold of…

Algebraic Geometry · Mathematics 2007-05-23 Kieran G. O'Grady

We discover a simple construction of a four-dimensional family of smooth surfaces of general type with $p_g(S)=q(S)=0$, $K^2_S=3$ with cyclic fundamental group $C_{14}$. We use a degeneration of the surfaces in this family to find…

Algebraic Geometry · Mathematics 2020-04-23 Lev Borisov , Enrico Fatighenti

We study the non-embddability property for a class of real hypersurfaces, called real hypersurfaces of involution type, into the sphere in the low codimensional case, by making use of property of a naturally related Gauss curvature. We also…

Complex Variables · Mathematics 2012-10-16 Xiaojun Huang , Shanyu Ji , Brandon Lee

We prove that the maximal number of conics, a priori irreducible of reducible, on a smooth spatial quartic surface is 800, realized by a unique quartic. We also classify quartics with many (at least 720) conics. The maximal number of real…

Algebraic Geometry · Mathematics 2026-02-12 Alex Degtyarev
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