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arXiv · 1811.03892

Graded Betti numbers of balanced simplicial complexes

Martina Juhnke-Kubitzke·Lorenzo Venturello
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Abstract

We prove upper bounds for the graded Betti numbers of Stanley-Reisner rings of balanced simplicial complexes. Along the way we show bounds for Cohen-Macaulay graded rings $S/I$, where $S$ is a polynomial ring and $I\subseteq S$ is an homogeneous ideal containing a certain number of generators in degree 2, including the squares of the variables. Using similar techniques we provide upper bounds for the number of linear syzygies for Stanley-Reisner of balanced normal pseudomanifolds. Moreover, we compute explicitly the graded Betti numbers of cross-polytopal stacked spheres, and show that they only depend on the dimension and the number of vertices, rather than also the combinatorial type.

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Martina Juhnke-Kubitzke, Lorenzo Venturello. 2018-11-09. Graded Betti numbers of balanced simplicial complexes. https://arxiv.org/abs/1811.03892

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