On the $k$-volume rigidity of a simplicial complex in ${\mathbb{R}}^d$

Abstract

We define a generic rigidity matroid for $k$-volumes of a simplicial complex in ${\mathbb{R}}^d$, and prove that for $2\le k\le d-1$ it has the same rank as the classical generic $d$-rigidity matroid on the same vertex set (namely, the case $k=1$). This is in contrast with the $k=d$ case, previously studied by Lubetzky and Peled, which presents a different behavior. We conjecture a characterization for the bases of this matroid in terms of $d$-rigidity of the $1$-skeleton of the complex and a combinatorial Hall condition on incidences of edges in $k$-faces.