The Cycle Rank Threshold: Perfect Matchings and Bipartite Parter Graphs
Abstract
A graph on n vertices is called a Parter graph if there exists a nonsingular symmetric matrix, whose nonzero off-diagonal entries correspond exactly to the edges of the graph, such that all of its principal submatrices of order n−1 are singular. Previously, a graph satisfying this condition was said to have property~(P). It was proved that, for bipartite graphs of cycle rank at most 3, being a Parter graph is equivalent to the existence of a perfect matching. We extend this result to cycle rank 4, proving that every bipartite graph of cycle rank at most 4 is a Parter graph if and only if it has a perfect matching. Furthermore, we show that this bound is sharp by constructing, for every integer r≥5, a connected balanced bipartite Parter graph of cycle rank r that has no perfect matching.
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BibTeX
@misc{arunkumar2026cycle,
title = {{The Cycle Rank Threshold: Perfect Matchings and Bipartite Parter Graphs}},
author = {G. Arunkumar and Puja Samanta},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2608.09869},
eprint = {2608.09869},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.09869},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Cycle Rank Threshold: Perfect Matchings and Bipartite Parter Graphs
AU - G. Arunkumar
AU - Puja Samanta
PY - 2026
DA - 2026/09/13
PB - arXiv
DO - 10.48550/arxiv.2608.09869
UR - https://arxiv.org/abs/2608.09869
AB - A graph on n vertices is called a Parter graph if there exists a nonsingular symmetric matrix, whose nonzero off-diagonal entries correspond exactly to the edges of the graph, such that all of its principal submatrices of order n−1 are singular. Previously, a graph satisfying this condition was said to have property~(P). It was proved that, for bipartite graphs of cycle rank at most 3, being a Parter graph is equivalent to the existence of a perfect matching. We extend this result to cycle rank 4, proving that every bipartite graph of cycle rank at most 4 is a Parter graph if and only if it has a perfect matching. Furthermore, we show that this bound is sharp by constructing, for every integer r≥5, a connected balanced bipartite Parter graph of cycle rank r that has no perfect matching.
ER -