English

Classifying closed 2-orbifolds with Euler characteristics

Differential Geometry 2011-04-12 v1 Algebraic Topology

Abstract

We determine the extent to which the collection of Γ\Gamma-Euler-Satake characteristics classify closed 2-orbifolds. In particular, we show that the closed, connected, effective, orientable 2-orbifolds are classified by the collection of Γ\Gamma-Euler-Satake characteristics corresponding to free or free abelian Γ\Gamma and are not classified by those corresponding to any finite collection of finitely generated discrete groups. Similarly, we show that such a classification is not possible for non-orientable 2-orbifolds and any collection of Γ\Gamma, nor for noneffective 2-orbifolds. As a corollary, we generate families of orbifolds with the same Γ\Gamma-Euler-Satake characteristics in arbitrary dimensions for any finite collection of Γ\Gamma; this is used to demonstrate that the Γ\Gamma-Euler-Satake characteristics each constitute new invariants of orbifolds.

Keywords

Cite

@article{arxiv.0902.2220,
  title  = {Classifying closed 2-orbifolds with Euler characteristics},
  author = {Whitney DuVal and John Schulte and Christopher Seaton and Bradford Taylor},
  journal= {arXiv preprint arXiv:0902.2220},
  year   = {2011}
}

Comments

17 pages

R2 v1 2026-06-21T12:11:04.261Z