English

Point-pushing actions for manifolds with boundary

Algebraic Topology 2023-03-07 v3 Geometric Topology

Abstract

Given a manifold MM and a point in its interior, the point-pushing map describes a diffeomorphism that pushes the point along a closed path. This defines a homomorphism from the fundamental group of MM to the group of isotopy classes of diffeomorphisms of MM that fix the basepoint. This map is well-studied in dimension d=2d = 2 and is part of the Birman exact sequence. Here we study, for any d3d \geqslant 3 and k1k \geqslant 1, the map from the kk-th braid group of MM to the group of homotopy classes of homotopy equivalences of the kk-punctured manifold MzM \smallsetminus z, and analyse its injectivity. Equivalently, we describe the monodromy of the universal bundle that associates to a configuration zz of size kk in MM its complement, the space MzM \smallsetminus z. Furthermore, motivated by our work on the homology of configuration-mapping spaces, we describe the action of the braid group of MM on the fibres of configuration-mapping spaces.

Keywords

Cite

@article{arxiv.2007.11613,
  title  = {Point-pushing actions for manifolds with boundary},
  author = {Martin Palmer and Ulrike Tillmann},
  journal= {arXiv preprint arXiv:2007.11613},
  year   = {2023}
}

Comments

33 pages, 8 figures. Final version; to appear in Groups, Geometry, and Dynamics. v3: Added new section 8 about the kernel of the point-pushing map. v2: Added new section 7 with examples

R2 v1 2026-06-23T17:19:34.864Z