scholarly journals Profinite genus of the fundamental groups of compact flat manifolds with holonomy group of prime order

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Genildo de Jesus Nery
Keyword(s):  
Fundamental Group ◽  
Prime Order ◽  
Isomorphism Class ◽  
Holonomy Group ◽  
Fundamental Groups ◽  
Flat Manifold ◽  
Profinite Completion ◽  
Compact Flat Manifolds ◽  
Flat Manifolds

Abstract In this article, we calculate the profinite genus of the fundamental group of an 𝑛-dimensional compact flat manifold 𝑋 with holonomy group of prime order. As consequence, we prove that if n ⩽ 21 n\leqslant 21 , then 𝑋 is determined among all 𝑛-dimensional compact flat manifolds by the profinite completion of its fundamental group. Furthermore, we characterize the isomorphism class of the profinite completion of the fundamental group of 𝑋 in terms of the representation genus of its holonomy group.

scholarly journals Bieberbach groups and flat manifolds with finite abelian holonomy from Artin braid groups

2021 ◽  
Author(s):  
Oscar Ocampo
Keyword(s):  
Fundamental Group ◽  
Abelian Subgroup ◽  
Holonomy Group ◽  
Braid Groups ◽  
Crystallographic Group ◽  
Flat Manifold ◽  
Kahler Geometry ◽  
Bieberbach Group ◽  
Odd Order ◽  
Flat Manifolds

Let [Formula: see text]. In this paper, we show that for any abelian subgroup [Formula: see text] of [Formula: see text] the crystallographic group [Formula: see text] has Bieberbach subgroups [Formula: see text] with holonomy group [Formula: see text]. Using this approach, we obtain an explicit description of the holonomy representation of the Bieberbach group [Formula: see text]. As an application, when the holonomy group is cyclic of odd order, we study the holonomy representation of [Formula: see text] and determine the existence of Anosov diffeomorphisms and Kähler geometry of the flat manifold [Formula: see text] with fundamental group the Bieberbach group [Formula: see text].

Two papers which changed my life: Mil nor's seminal work on flat manifolds and bundles

2014 ◽  
Keyword(s):  
Fundamental Group ◽  
Characteristic Classes ◽  
Fundamental Groups ◽  
Seminal Work ◽  
Affine Manifolds ◽  
Recent Developments ◽  
Auslander Conjecture ◽  
History Of ◽  
Flat Manifolds ◽  
Curvature Zero

This chapter surveys developments arising from John Milnor's 1958 paper, “On the existence of a connection with curvature zero” and his 1977 paper, “On fundamental groups of complete affinely flat manifolds.” The former deeply influenced the theory of characteristic classes of flat bundles, and the latter clarified the theory of affine manifolds, setting the stage for its future flourishing. This chapter begins with some reminiscences on Milnor. It then describes the history of the Milnor–Wood inequality and the Auslander Conjecture and then proceeds to more recent developments, including a description of Margulis space-times, a startling example of an affine three-manifold with free fundamental group.

Filling words in fundamental groups of Riemann surfaces

2013 ◽  
Vol 50 (1) ◽  
pp. 31-50
Author(s):  
C. Zhang
Keyword(s):  
Riemann Surface ◽  
Fundamental Group ◽  
Riemann Surfaces ◽  
Fundamental Groups ◽  
Closed Geodesics ◽  
New Words

The purpose of this article is to utilize some exiting words in the fundamental group of a Riemann surface to acquire new words that are represented by filling closed geodesics.

scholarly journals Computing the fundamental group of a higher-rank graph

2021 ◽  
pp. 1-12
Author(s):  
Sooran Kang ◽  
David Pask ◽  
Samuel B.G. Webster
Keyword(s):  
Fundamental Group ◽  
Homology Group ◽  
Klein Bottle ◽  
Fundamental Groups ◽  
The Third ◽  
Higher Rank ◽  
The One ◽  
Standard Presentation

Abstract We compute a presentation of the fundamental group of a higher-rank graph using a coloured graph description of higher-rank graphs developed by the third author. We compute the fundamental groups of several examples from the literature. Our results fit naturally into the suite of known geometrical results about higher-rank graphs when we show that the abelianization of the fundamental group is the homology group. We end with a calculation which gives a non-standard presentation of the fundamental group of the Klein bottle to the one normally found in the literature.

scholarly journals Fundamental Group of Simple C*-algebras with Unique Trace III

2012 ◽  
Vol 64 (3) ◽  
pp. 573-587 ◽  
Author(s):  
Norio Nawata
Keyword(s):  
Fundamental Group ◽  
Lower Semicontinuous ◽  
Classification Theorem ◽  
Fundamental Groups ◽  
C Algebras ◽  
Scalar Multiple ◽  
Unique Trace ◽  
Densely Defined

Abstract We introduce the fundamental group ℱ(A) of a simple σ-inital C*-algebra A with unique (up to scalar multiple) densely defined lower semicontinuous trace. This is a generalization of Fundamental Group of Simple C*-algebras with Unique Trace I and II by Nawata andWatatani. Our definition in this paper makes sense for stably projectionless C*-algebras. We show that there exist separable stably projectionless C*-algebras such that their fundamental groups are equal to ℝ×+ by using the classification theorem of Razak and Tsang. This is a contrast to the unital case in Nawata and Watatani. This study is motivated by the work of Kishimoto and Kumjian.

Elementary amenable groups and 4-manifolds with Euler characteristic 0

1991 ◽  
Vol 50 (1) ◽  
pp. 160-170 ◽  
Author(s):  
Jonathan A. Hillman
Keyword(s):  
Normal Subgroup ◽  
Fundamental Group ◽  
Euler Characteristic ◽  
Fundamental Groups ◽  
Normal Subgroups ◽  
Euler Characteristics ◽  
Amenable Groups ◽  
Amenable Subgroup ◽  
Finite Subgroups ◽  
Torsion Free

AbstractWe extend earlier work relating asphericity and Euler characteristics for finite complexes whose fundamental groups have nontrivial torsion free abelian normal subgroups. In particular a finitely presentable group which has a nontrivial elementary amenable subgroup whose finite subgroups have bounded order and with no nontrivial finite normal subgroup must have deficiency at most 1, and if it has a presentation of deficiency 1 then the corresponding 2-complex is aspherical. Similarly if the fundamental group of a closed 4-manifold with Euler characteristic 0 is virtually torsion free and elementary amenable then it either has 2 ends or is virtually an extension of Z by a subgroup of Q, or the manifold is asphencal and the group is virtually poly- Z of Hirsch length 4.

Finiteness of Isomorphism Classes of Hyperbolic Polycurves with Prescribed Fundamental Groups

2020 ◽  
Author(s):  
Koichiro Sawada
Keyword(s):  
Fundamental Group ◽  
Profinite Group ◽  
Fundamental Groups ◽  
Isomorphism Classes

Abstract In the present paper, we show that there are at most finitely many isomorphism classes of hyperbolic polycurves (i.e., successive extensions of families of hyperbolic curves) over certain types of fields whose étale fundamental group is isomorphic to a prescribed profinite group.

scholarly journals On l-Adic Iterated Integrals, III Galois Actions on Fundamental Groups

2005 ◽  
Vol 178 ◽  
pp. 1-36 ◽  
Author(s):  
Zdzisław Wojtkowiak
Keyword(s):  
Fundamental Group ◽  
Galois Representations ◽  
Fundamental Groups ◽  
Iterated Integrals ◽  
Galois Actions

We continue to study l-adic iterated integrals introduced in the first part. We shall calculate explicitly l-adic logarithm and l-adic polylogarithms. Next we shall use these results to study Galois representations on the fundamental group of .

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