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Related papers: Some open questions on arithmetic Zariski pairs

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In this paper, we introduce \textit{splitting numbers} of subvarieties in a smooth variety for a Galois cover, and prove that the splitting numbers are invariant under certain homeomorphisms. By splitting numbers, we give a necessary and…

Algebraic Geometry · Mathematics 2016-03-18 Taketo Shirane

We introduce a new topological invariant of complex line arrangements in the complex projective plane, derived from the interaction between their complement and the boundary of a regular neighbourhood. The motivation is to identify Zariski…

Geometric Topology · Mathematics 2026-05-29 Adrien Rodau

We apply numerical algebraic geometry to the invariant-theoretic problem of detecting symmetries between two plane algebraic curves. We describe an efficient equality test which determines, with "probability-one", whether or not two…

Algebraic Geometry · Mathematics 2020-12-16 Timothy Duff , Michael Ruddy

A computation shows that there are 77 (up to scalar shifts) possible pairs of integer coefficient polynomials of degree five, having roots of unity as their roots, and satisfying the conditions of Beukers and Heckman [1], so that the…

Group Theory · Mathematics 2018-11-27 Jitendra Bajpai , Sandip Singh

There is a close relationship between the embedded topology of complex plane curves and the (group-theoretic) arithmetic of elliptic curves. In a recent paper, we studied the topology of some arrangements of curves which include a special…

Algebraic Geometry · Mathematics 2020-12-10 E. Artal Bartolo , S. Bannai , T. Shirane , H. Tokunaga

We find a new Zariski pair with non-isomorphic fundamental groups that consists of degree $ 8 $ conic-line arrangements. Each arrangement has three conics and two lines. We use the Zariski-van Kampen Theorem and some known Coxeter groups to…

Algebraic Geometry · Mathematics 2025-03-26 Meirav Amram , Robert Shwartz , Uriel Sinichkin , Sheng-Li Tan , Hiro-o Tokunaga

We formulate and prove a weighted version of Zariski's hyperplane section theorem on the topological fundamental groups of the complements of hypersurfaces in a projective space. As an application, we calculate fundamental groups of the…

alg-geom · Mathematics 2008-02-03 Ichiro Shimada

We investigate Zariski multiples of plane curves $Z_1, \dots, Z_N$ such that each $Z_i$ is a union of a smooth quartic curve, some of its bitangents, and some of its 4-tangent conics. We show that, for plane curves of this type, the…

Algebraic Geometry · Mathematics 2022-09-27 Ichiro Shimada

We provide a geometric elementary proof of the fact that an analytic plane branch is analytically equivalent to one whose terms corresponding to contacts with holomorphic one-forms -- except for Zariski's $\lambda$-invariant -- are zero (so…

Algebraic Geometry · Mathematics 2019-03-21 Pedro Fortuny Ayuso

In this paper we describe and characterize the fundamental group of the complement to generic fiber-type curves, i.e. unions of (the closure of) finitely many generic fibers of a component-free pencil $F=[f:g]:\mathbb C\mathbb…

Algebraic Geometry · Mathematics 2025-07-22 José I. Cogolludo-Agustín , Eva Elduque

A framework is developed to describe the Zariski topologies on the prime and primitive spectra of a quantum algebra $A$ in terms of the (known) topologies on strata of these spaces and maps between the collections of closed sets of…

Quantum Algebra · Mathematics 2013-11-04 K. A. Brown , K. R. Goodearl

We extend and apply the Galois theory of linear differential equations equipped with the action of an endomorphism. The Galois groups in this Galois theory are difference algebraic groups and we use structure theorems for these groups to…

Commutative Algebra · Mathematics 2015-04-22 Lucia Di Vizio , Charlotte Hardouin , Michael Wibmer

We construct new examples of singular projective plane curves whose complements have finite and non-abelian fundamental groups, by generalizing the classical three cuspidal quartic curve discovered by Zariski.

alg-geom · Mathematics 2008-02-03 Ichiro Shimada

We construct exponentially large collections of pairwise distinct equisingular deformation families of irreducible plane curves sharing the same sets of singularities. The fundamental groups of all curves constructed are abelian.

Algebraic Geometry · Mathematics 2009-07-02 Alex Degtyarev

The existence of Alexander-equivalent Zariski pairs dealing with irreducible curves of degree 6 was proved by A. Degtyarev. However, up to now, no explicit example of such a pair was available (only the existence was known). In this paper,…

Algebraic Geometry · Mathematics 2014-02-26 Christophe Eyral , Mutsuo Oka

We generalize the notion of a projective profinite group to a projective pair of a profinite group and a closed subgroup. We establish the connection with Pseudo Algebraically Closed (PAC) extensions of PAC fields: Let M be an algebraic…

Group Theory · Mathematics 2008-10-31 Lior Bary-Soroker

This PhD deals with the notion of pseudo algebraically closed (PAC) extensions of fields. It develops a group-theoretic machinery, based on a generalization of embedding problems, to study these extensions. Perhaps the main result is that…

Number Theory · Mathematics 2009-07-17 Lior Bary-Soroker

We extend results of Cogolludo-Agustin and Libgober relating the Alexander polynomial of a plane curve $C$ with the Mordell--Weil rank of certain isotrivial families of jacobians over $\mathbf{P}^2$ of discriminant $C$. In the second part…

Algebraic Geometry · Mathematics 2016-04-04 Remke Kloosterman

In this note, we present two pairs of conic-line arrangements admitting a unique conic and that form Zariski pairs, both of degree $9$. Their topologies are distinguished using the connected numbers.

Algebraic Geometry · Mathematics 2024-10-08 Shinzo Bannai , Benoît Guerville-Ballé , Taketo Shirane

A $k$-Artal arrangement is a reducible algebraic curve composed of a smooth cubic and $k$ inflectional tangents. By studying the topological properties of their subarrangements, we prove that for $k=3,4,5,6$, there exist Zariski pairs of…

Algebraic Geometry · Mathematics 2016-07-27 Shinzo Bannai , Benoît Guerville-Ballé , Taketo Shirane , Hiro-o Tokunaga