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The cd-index of a semi-Eulerian poset

Algebra & Discrete Mathematics

Speaker: Jose Samper, PUC Chile
Location: 1147 MSB
Start time: Tue, Feb 4 2025, 2:10PM

 We generalize the definition of the $cd$-index of a Eulerian poset to the class of semi-Eulerian posets. For connected simplicial semi-Eulerian Buchsbaum posets, we show that all coefficients of the $cd$-index are nonnegative. This proves a conjecture of Novik for odd-dimensional manifolds and extends it to the even-dimensional case. Joint work with Martina Juhnke and Lorenzo Venturello.