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arXiv · 2506.20087

On minors of non-hamiltonian graphs

On-Hei Solomon Lo
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Abstract

A theorem of Tutte states that every 4-connected non-hamiltonian graph contains $K_{3,3}$ as a minor. We strengthen this result by proving that such a graph must contain $K_{3,4}$ as a minor, thereby confirming a special case of a conjecture posed by Chen, Yu, and Zang in a strong form. This result may be viewed as a step toward characterizing the minor-minimal 4-connected non-hamiltonian graphs. As a 3-connected analog, Ding and Marshall conjectured that every 3-connected non-hamiltonian graph has a minor of $K_{3,4}$, $\mathfrak{Q}^+$, or the Herschel graph, where $\mathfrak{Q}^+$ is obtained from the cube by adding a new vertex adjacent to three independent vertices. We confirm this conjecture.

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On-Hei Solomon Lo. 2025-06-25. On minors of non-hamiltonian graphs. https://arxiv.org/abs/2506.20087

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