The ACO Seminar (2023–2024)

The study of matroids and their invariants has undergone remarkable developments in recent years. In particular, many long-standing conjectures concerning inequalities that are satisfied between certain invariants, such as the number of flats of a given rank, associated to a given matroid, have been resolved. We take a different perspective and consider inequalities between invariants of different matroids. By employing combinatorial and algebraic methods, we prove several results, with our main result being that the flag h-vector is nonincreasing under weak maps.