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arXiv · 2407.18144

Conflict-free Hypergraph Matchings and Coverings

Felix Joos·Dhruv Mubayi·Zak Smith
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Abstract

Recent work showing the existence of conflict-free almost-perfect hypergraph matchings has found many applications. We show that, assuming certain simple degree and codegree conditions on the hypergraph $ \mathcal{H} $ and the conflicts to be avoided, a conflict-free almost-perfect matching can be extended to one covering all of the vertices in a particular subset of $ V(\mathcal{H}) $, by using an additional set of edges; in particular, we ensure that our matching avoids all of a further set of conflicts, which may consist of both old and new edges. This setup is useful for various applications, and our main theorem provides a black box which encapsulates many long and tedious calculations, massively simplifying the proofs of results in generalised Ramsey theory.

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Felix Joos, Dhruv Mubayi, Zak Smith. 2024-07-25. Conflict-free Hypergraph Matchings and Coverings. https://doi.org/10.1017/s0963548325100291

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