Elastic elements in 3-connected matroids
Abstract
It follows by Bixby's Lemma that if is an element of a -connected matroid , then either , the cosimplification of , or , the simplification of , is -connected. A natural question to ask is whether has an element such that both and are -connected. Calling such an element "elastic", in this paper we show that if , then has at least four elastic elements provided has no -element fans and, up to duality, has no -separating set that is the disjoint union of a rank- subset and a corank- subset of such that is isomorphic to a member or a single-element deletion of a member of a certain family of matroids.
Cite
@article{arxiv.2010.01797,
title = {Elastic elements in 3-connected matroids},
author = {George Drummond and Zachary Gershkoff and Susan Jowett and Charles Semple and Jagdeep Singh},
journal= {arXiv preprint arXiv:2010.01797},
year = {2021}
}
Comments
20 pages, 1 figure. The main result (Theorem 1) in the original paper is incorrect. In particular, as well as 4-element fans, there is also a family of exceptions. An error in one of the earlier lemmas was missed. We have corrected the paper