Recorded 14 February 2025. José Alejandro Samper Casas of Pontificia Universidad Catolica de Chile presents "The cd-index of a semi-Eulerian complex" at IPAM's Computational Interactions between Algebra, Combinatorics, and Discrete Geometry Workshop. Abstract: 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. Learn more online at: https://www.ipam.ucla.edu/programs/workshops/computational-interactions-between-algebra-combinatorics-and-discrete-geometry/