Stellahedral geometry of matroids

C Eur, J Huh, M Larson - Forum of Mathematics, Pi, 2023 - cambridge.org
We use the geometry of the stellahedral toric variety to study matroids. We identify the
valuative group of matroids with the cohomology ring of the stellahedral toric variety and …

Tautological classes of matroids

A Berget, C Eur, H Spink, D Tseng - Inventiones mathematicae, 2023 - Springer
We introduce certain torus-equivariant classes on permutohedral varieties which we call
“tautological classes of matroids” as a new geometric framework for studying matroids …

Associahedra for finite‐type cluster algebras and minimal relations between g‐vectors

A Padrol, Y Palu, V Pilaud… - Proceedings of the …, 2023 - Wiley Online Library
We show that the mesh mutations are the minimal relations among the gg‐vectors with
respect to any initial seed in any finite‐type cluster algebra. We then use this algebraic result …

Tropical flag varieties

M Brandt, C Eur, L Zhang - Advances in Mathematics, 2021 - Elsevier
Flag matroids are combinatorial abstractions of flags of linear subspaces, just as matroids
are of linear subspaces. We introduce the flag Dressian as a tropical analogue of the partial …

Simplicial generation of Chow rings of matroids

S Backman, C Eur, C Simpson - Journal of the European Mathematical …, 2023 - ems.press
We introduce a presentation of the Chow ring of a matroid by a new set of generators, called
“simplicial generators.” These generators are analogous to nef divisors on projective toric …

The geometry of geometries: matroid theory, old and new

F Ardila-Mantilla - Proc. Int. Cong. Math, 2022 - ems.press
The theory of matroids or combinatorial geometries originated in linear algebra and graph
theory, and has deep connections with many other areas, including field theory, matching …

Polypositroids

T Lam, A Postnikov - Forum of Mathematics, Sigma, 2024 - cambridge.org
We initiate the study of a class of polytopes, which we coin polypositroids, defined to be
those polytopes that are simultaneously generalized permutohedra (or polymatroids) and …

Generalized permutahedra and positive flag Dressians

M Joswig, G Loho, D Luber… - International …, 2023 - academic.oup.com
We study valuated matroids, their tropical incidence relations, flag matroids, and total
positivity. This leads to a characterization of permutahedral subdivisions, namely …

Signed permutohedra, delta‐matroids, and beyond

C Eur, A Fink, M Larson, H Spink - Proceedings of the London …, 2024 - Wiley Online Library
We establish a connection between the algebraic geometry of the type BB permutohedral
toric variety and the combinatorics of delta‐matroids. Using this connection, we compute the …

Shard polytopes

A Padrol, V Pilaud, J Ritter - … Mathematics Research Notices, 2023 - academic.oup.com
For any lattice congruence of the weak order on permutations, Reading proved that gluing
together the cones of the braid fan that belong to the same congruence class defines a …