Abstract
We show that Kimura’s necessary and sufficient condition for the nonvanishingness of multigraded Betti numbers of edge ideals of chordal graphs can be extended to the larger family of weakly chordal graphs. We also obtain a description for the Betti numbers of edge ideals of threshold graphs in terms of the Euler characteristic of the independence complex of its induced subgraphs.
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The authors thank the referees for their useful comments and suggestions which substantially improved the exposition of the paper.
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José Martínez-Bernal was supported by SNI México. Oscar A. Pizá-Morales and Miguel A. Valencia-Bucio were supported by CONACyT México.
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Martínez-Bernal, J., Pizá-Morales, O.A. & Valencia-Bucio, M.A. Nonvanishing Betti numbers of edge ideals of weakly chordal graphs. J Algebr Comb 58, 279–290 (2023). https://doi.org/10.1007/s10801-023-01248-0
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DOI: https://doi.org/10.1007/s10801-023-01248-0
Keywords
- Betti numbers
- Euler characteristic
- Hochster’s formula
- Stanley–Reisner ring
- Weakly chordal graph
- Threshold graph