2025/06/23 by Panzer, Erik
#Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2506.18788
We prove relations between the number of k-connected components of a graph, Crapo's invariant β(M) of a matroid, and Speyer's polynomial gM(t). These yield a simple interpretation of gM'(-1) when M is graphic or cographic. Furthermore, we improve Ferroni's algorithm to compute gM(t) and provide an implementation and an extensive data set. These calculations reveal a large number of graph theoretic constraints on the second derivative gM''(-1), which we thus advertise as an intriguing new invariant of graphs. We also propose a relation between the flow polynomial and gM''(0) for cubic graphs.