Volume 24, issue 2 (2020)

 Recent Issues
 The Journal About the Journal Editorial Board Editorial Interests Editorial Procedure Subscriptions Submission Guidelines Submission Page Policies for Authors Ethics Statement ISSN (electronic): 1364-0380 ISSN (print): 1465-3060 Author Index To Appear Other MSP Journals
Kähler groups and subdirect products of surface groups

Claudio Llosa Isenrich

Geometry & Topology 24 (2020) 971–1017
Abstract

We present a construction that produces infinite classes of Kähler groups that arise as fundamental groups of fibres of maps to higher-dimensional tori. Following the work of Delzant and Gromov, there is great interest in knowing which subgroups of direct products of surface groups are Kähler. We apply our construction to obtain new classes of irreducible, coabelian Kähler subgroups of direct products of $r$ surface groups. These cover the full range of possible finiteness properties of irreducible subgroups of direct products of $r$ surface groups: for any $r\ge 3$ and $2\le k\le r-1$, our classes of subgroups contain Kähler groups that have a classifying space with finite $k$–skeleton while not having a classifying space with finitely many $\left(k+1\right)$–cells.

We also address the converse question of finding constraints on Kähler subdirect products of surface groups and, more generally, on homomorphisms from Kähler groups to direct products of surface groups. We show that if a Kähler subdirect product of $r$ surface groups admits a classifying space with finite $k$–skeleton for $k>\frac{r}{2}$, then it is virtually the kernel of an epimorphism from a direct product of surface groups onto a free abelian group of even rank.

We have not been able to recognize your IP address 34.232.63.94 as that of a subscriber to this journal.
Online access to the content of recent issues is by subscription, or purchase of single articles.

or by using our contact form.

Keywords
Kähler groups, surface groups, branched covers, homological finiteness properties
Mathematical Subject Classification 2010
Primary: 20F65, 32J27
Secondary: 20J05, 32Q15