Extension complexity of low-dimensional polytopes
Kwan, Matthew Alan
Sauermann, Lisa
Zhao, Yufei
Sometimes, it is possible to represent a complicated polytope as a projection of a much simpler polytope. To quantify this phenomenon, the extension complexity of a polytope P is defined to be the minimum number of facets of a (possibly higher-dimensional) polytope from which P can be obtained as a (linear) projection. This notion is motivated by its relevance to combinatorial optimisation, and has been studied intensively for various specific polytopes associated with important optimisation problems. In this paper we study extension complexity as a parameter of general polytopes, more specifically considering various families of low-dimensional polytopes. First, we prove that for a fixed dimension d, the extension complexity of a random d-dimensional polytope (obtained as the convex hull of random points in a ball or on a sphere) is typically on the order of the square root of its number of vertices. Second, we prove that any cyclic n-vertex polygon (whose vertices lie on a circle) has extension complexity at most 24√n. This bound is tight up to the constant factor 24. Finally, we show that there exists an no(1)-dimensional polytope with at most n vertices and extension complexity n1−o(1). Our theorems are proved with a range of different techniques, which we hope will be of further interest.
American Mathematical Society
2022
info:eu-repo/semantics/article
doc-type:article
text
http://purl.org/coar/resource_type/c_6501
https://research-explorer.ista.ac.at/record/11443
Kwan MA, Sauermann L, Zhao Y. Extension complexity of low-dimensional polytopes. <i>Transactions of the American Mathematical Society</i>. 2022;375(6):4209-4250. doi:<a href="https://doi.org/10.1090/tran/8614">10.1090/tran/8614</a>
eng
info:eu-repo/semantics/altIdentifier/doi/10.1090/tran/8614
info:eu-repo/semantics/altIdentifier/issn/0002-9947
info:eu-repo/semantics/altIdentifier/issn/1088-6850
info:eu-repo/semantics/altIdentifier/wos/000798461500001
info:eu-repo/semantics/altIdentifier/arxiv/2006.08836
info:eu-repo/semantics/openAccess