Uniquely realisable graphs in polyhedral normed spaces

Abstract

A framework (a straight-line embedding of a graph into a normed space allowing edges to cross) is globally rigid if any other framework with the same edge lengths with respect to the chosen norm is an isometric copy. We investigate global rigidity in polyhedral normed spaces: normed spaces where the unit ball is a polytope. We first provide a deterministic algorithm for checking whether or not a framework in a polyhedral normed space is globally rigid. After showing that determining if a framework is globally rigid is NP-Hard, we then provide necessary conditions for global rigidity for generic frameworks. We obtain stronger results for generic frameworks in $\ell_\infty^d$ (the vector space $\mathbb{R}^d$ equipped with the $\ell_\infty$ metric) including an exact characterisation of global rigidity when $d=2$, and an easily-computable sufficient condition for global rigidity using edge colourings. Our 2-dimensional characterisation also has a surprising consequence: Hendrickson's global rigidity condition fails for generic frameworks in $\ell_\infty^2$.