Published online by Cambridge University Press: 20 November 2018
Let ${{M}_{n}}$ be the variety of spatial polygons
$P\,=\,({{a}_{1}},\,{{a}_{2}},...,{{a}_{n}})$ whose sides are vectors
${{a}_{i}}\,\in \,{{\mathbf{R}}^{3}}$ of length
$\left| {{a}_{i}} \right|\,=\,1\,(1\,\le \,i\,\le \,n)$, up to motion in
${{\mathbf{R}}^{3}}$. It is known that for odd
$n$,
${{M}_{n}}$ is a smooth manifold, while for even
$n$,
${{M}_{n}}$ has cone-like singular points. For odd
$n$, the rational homology of
${{M}_{n}}$ was determined by Kirwan and Klyachko [6], [9]. The purpose of this paper is to determine the rational homology of
${{M}_{n}}$ for even
$n$. For even
$n$, let
${{\tilde{M}}_{n}}$ be the manifold obtained from
${{M}_{n}}$ by the resolution of the singularities. Then we also determine the integral homology of
${{\tilde{M}}_{n}}$.