On the Number of Facets of Polytopes Representing Comparative Probability Orders
Combinatorics
2023-08-23 v1
Abstract
Fine and Gill (1973) introduced the geometric representation for those comparative probability orders on n atoms that have an underlying probability measure. In this representation every such comparative probability order is represented by a region of a certain hyperplane arrangement. Maclagan (1999) asked how many facets a polytope, which is the closure of such a region, might have. We prove that the maximal number of facets is at least F_{n+1}, where F_n is the nth Fibonacci number. We conjecture that this lower bound is sharp. Our proof is combinatorial and makes use of the concept of flippable pairs introduced by Maclagan. We also obtain an upper bound which is not too far from the lower bound.
Keywords
Cite
@article{arxiv.1103.3938,
title = {On the Number of Facets of Polytopes Representing Comparative Probability Orders},
author = {Ilya Chevyrev and Dominic Searles and Arkadii Slinko},
journal= {arXiv preprint arXiv:1103.3938},
year = {2023}
}
Comments
13 pages