Séminaire Lotharingien de Combinatoire, 95B.23 (2026), 12 pp.

Raj Gandhi and Ethan Partida

Algebraic Cobordism Rings of Wonderful Varieties and Matroids

Abstract. We prove a Feichtner-Yuzvinsky presentation and a simplicial presentation for the algebraic cobordism ring of the toric variety of the Bergman fan of any loopless matroid in terms of the lattice of flats of the matroid and the universal formal group law. For an essential hyperplane arrangement H, we prove that the algebraic cobordism ring of the wonderful variety WH of H and the algebraic cobordism ring of the toric variety of the matroid underlying H are isomorphic, and that both rings coincide with the complex cobordism ring of WH.


Received: November 15, 2025. Accepted: February 15, 2026. Final version: April 1, 2026.

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