English

How to avoid collisions in 3D-realizations for moving graphs

Combinatorics 2021-05-06 v2

Abstract

If we parameterize the positions of all vertices of a given graph in the plane such that distances between adjacent vertices are fixed, we obtain a moving graph. An L-linkage is a realization of a moving graph in 3D-space, by representing edges using horizontal bars and vertices by vertical sticks. Vertical sticks are parallel revolute joints, while horizontal bars are links connecting them. We give a sufficient condition for a moving graph to have a collision-free L-linkage. Furthermore, we provide an algorithm guiding the construction of such a linkage when the moving graph fulfills the sufficient condition, via computing a height function for the edges (horizontal bars). In particular, we prove that any Dixon-1 moving graph has a collision-free L-linkage and no Dixon-2 moving graphs have collision-free L-linkages, where Dixon-1 and Dixon-2 moving graphs are two classic families of moving graphs.

Keywords

Cite

@article{arxiv.1904.13260,
  title  = {How to avoid collisions in 3D-realizations for moving graphs},
  author = {Jiayue Qi},
  journal= {arXiv preprint arXiv:1904.13260},
  year   = {2021}
}
R2 v1 2026-06-23T08:53:24.775Z