Explore matroid tautological classes in Types A and B through a 22-minute lecture delivered by Alex Fink from Queen Mary University of London at the Fields Institute. Delve into the intricacies of matroid theory, examining its applications and the magic it brings to mathematical concepts. Investigate the Hodge package, Type A root system, and Type B Delta matrix. Gain insights into the interconnections between Types A and B, and understand their significance in the broader context of algebraic geometry and combinatorics. This talk, part of the "Spec(Q-bar)" series, offers a deep dive into advanced mathematical concepts for those interested in expanding their knowledge of matroid theory and its applications.