Abstract
We investigate resolutions of letterplace ideals of posets. We develop topological results to compute their multigraded Betti numbers, and to give structural results on these Betti numbers. If the poset is a union of no more than c chains, we show that the Betti numbers may be computed from simplicial complexes of no more than c vertices. We also give a recursive procedure to compute the Betti diagrams when the Hasse diagram of P has tree structure.
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Acknowledgements
Most of this work was carried out while the first and the third authors were visiting the second author at the University of Bergen. The third author received support from the University of Bergen and his institute during his stay.
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D’Alì, A., Fløystad, G. & Nematbakhsh, A. Resolutions of letterplace ideals of posets. J Algebr Comb 45, 911–930 (2017). https://doi.org/10.1007/s10801-016-0729-z
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DOI: https://doi.org/10.1007/s10801-016-0729-z