Published online by Cambridge University Press: 20 November 2018
Monotone paths on zonotopes and the natural generalization to maximal chains in the poset of topes of an oriented matroid or arrangement of pseudo-hyperplanes are studied with respect to a kind of local move, called polygon move or flip. It is proved that any monotone path on a  
 $d$ -dimensional zonotope with  
 $n$  generators admits at least  
 $\left\lceil 2n/\left( n-d+2 \right) \right\rceil -1$  flips for all  
 $n\ge d+2\ge 4$  and that for any fixed value of  
 $n-d$ , this lower bound is sharp for infinitely many values of  
 $n$ . In particular, monotone paths on zonotopes which admit only three flips are constructed in each dimension  
 $d\ge 3$ . Furthermore, the previously known 2-connectivity of the graph of monotone paths on a polytope is extended to the 2-connectivity of the graph of maximal chains of topes of an oriented matroid. An application in the context of Coxeter groups of a result known to be valid for monotone paths on simple zonotopes is included.