Hamiltonian connectivity of some base-cobase graphs

Fuente: arXiv
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Main Authors: Martínez-Sandoval, Leonardo, Knauer, Kolja
Format: Preprint
Published: 2025
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author Martínez-Sandoval, Leonardo
Knauer, Kolja
author_facet Martínez-Sandoval, Leonardo
Knauer, Kolja
contents There has been wide interest in understanding which properties of base graphs of matroids extend to base-cobase graphs of matroids. A significant result of Naddef and Pulleyblank (1984) shows that the $1$-skeleton of any $(0,1)$-polytope is either a hypercube, or Hamiltonian-connected, i.e. there is a Hamiltonian path connecting any two vertices. In particular, this is true for base graphs of matroids. A natural question raised by Farber, Richter, and Shank (1985) is whether this extends to base-cobase graphs. First, we use the polytopal approach to show Hamiltonian connectivity of base-cobase graphs of series-parallel extensions of lattice path matroids. On the other hand, we show that this method extends to only very special classes related to identically self-dual matroids. Second, we show that base-cobase graphs of wheels and whirls are Hamiltonian connected. Last, we show that the regular matroid $R_{10}$ yields a negative answer to the question of Farber, Richter, and Shank.
format Preprint
id arxiv_https___arxiv_org_abs_2506_15049
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hamiltonian connectivity of some base-cobase graphs
Martínez-Sandoval, Leonardo
Knauer, Kolja
Combinatorics
Discrete Mathematics
There has been wide interest in understanding which properties of base graphs of matroids extend to base-cobase graphs of matroids. A significant result of Naddef and Pulleyblank (1984) shows that the $1$-skeleton of any $(0,1)$-polytope is either a hypercube, or Hamiltonian-connected, i.e. there is a Hamiltonian path connecting any two vertices. In particular, this is true for base graphs of matroids. A natural question raised by Farber, Richter, and Shank (1985) is whether this extends to base-cobase graphs. First, we use the polytopal approach to show Hamiltonian connectivity of base-cobase graphs of series-parallel extensions of lattice path matroids. On the other hand, we show that this method extends to only very special classes related to identically self-dual matroids. Second, we show that base-cobase graphs of wheels and whirls are Hamiltonian connected. Last, we show that the regular matroid $R_{10}$ yields a negative answer to the question of Farber, Richter, and Shank.
title Hamiltonian connectivity of some base-cobase graphs
topic Combinatorics
Discrete Mathematics
url https://arxiv.org/abs/2506.15049