English

Indecomposable $PD_3$-complexes

Geometric Topology 2014-07-22 v4 Algebraic Topology

Abstract

We show that if XX is an indecomposable PD3PD_3-complex and π1(X)isthefundamentalgroupofareducedfinitegraphoffinitegroupsbutisnotvirtuallycyclicthen\pi_1(X) is the fundamental group of a reduced finite graph of finite groups but is not virtually cyclic then Xisorientable,theunderlyinggraphisatree,alltheedgegroupsare is orientable, the underlying graph is a tree, all the edge groups are Z/2Zandallbutatmostoneofthevertexgroupsisdihedraloforder and all but at most one of the vertex groups is dihedral of order 2mwith with modd.Everysuchgroupisrealizedbysome odd. Every such group is realized by some PD_3complex.Wealsoproposeastrategyfortacklingthequestionofwhetherevery-complex. We also propose a strategy for tackling the question of whether every PD_3$-complex has a finite covering space which is homotopy equivalent to a closed orientable 3-manifold.

Keywords

Cite

@article{arxiv.0808.1775,
  title  = {Indecomposable $PD_3$-complexes},
  author = {J. A. Hillman},
  journal= {arXiv preprint arXiv:0808.1775},
  year   = {2014}
}

Comments

22 pages. The determination of the possible fundamental groups has been completed. A lemma has been added to Section 2, and the main theorem (5.2) has been strengthened

R2 v1 2026-06-21T11:09:53.991Z