Spring 2026: Talking About Combinatorial Objects Seminar (TACOS)

Topic: Hyperplane arrangements and coinvariant algebras

Fridays: 12:30-2:00pm, Location: 939 Evans Hall (Lunch at 12 on patio)

Organizers: Sylvie Corteel, Mitsuki Hanada, and John Lentfer.

References: Superspace coinvariants and hyperplane arrangements (Angarone, Commins, Karn, Murai, Rhoades), this is the main paper we will be starting with;
The Hilbert series of the superspace coinvariant ring (Rhoades and Wilson), this covers the reduction;
q-Stirling numbers in type B (Sagan and Swanson), this covers some of the combinatorics and conjectures;
A proof of the Fields conjectures (Murai, Rhoades, Wilson), this is the follow-up to Angarone et al. and will be our second paper we cover.
The schedule is subject to change as we may need more than one week to cover a listed topic.

Date Speaker Topic Notes
1/30 John Lentfer Background on coinvariant algebras
2/6 John Lentfer Background on coinvariant algebras
2/13 Mitsuki Hanada Outline of Angarone et al.
2/20 Yuhan Jiang The reduction of Rhoades--Wilson
2/27 Swapnil Garg Introduction to hyperplane arrangements and Soloman--Terao algebras
3/6 Patty Commins Hyperplane arrangements in Angarone et al.
3/13 Patty Commins Hyperplane arrangements in Angarone et al.
3/20 John Lentfer Outline of Murai, Rhoades, Wilson First 20 minutes will be Patty finishing her talk.
3/27 No seminar - Spring break
4/3 John Lentfer Outline of Murai, Rhoades, Wilson
4/10 No seminar
4/17 Ibrahim Ahmad Superspace coinvariant rings and the Springer resolution
4/24 Patty Commins Quasisymmetric coinvariants and Catalan numbers