Ohio State University Algebraic Geometry Seminar


Ohio State University Algebraic Geometry Seminar Year 2025-2026 Time: Tuesdays 10:20-11:15am Location: MW 154 (in person) or Zoom (virtual, email the organizers for the Zoom coordinates)

Schedule of talks:


TIME	SPEAKER	TITLE
August 26 Tue, 10:20am	Adrian Neff (OSU)	Residues and contractions of genus one curves
September 9 Tue, 10:20am	Yiyu Wang (OSU)	The local Euler obstruction of a matroid Schubert variety
September 23 Tue, 10:20am	( )
September 30 Tue, 10:20am	Jingxiang Ma (Sheffield)
October 7 Tue, 10:20am	( )
October 14 Tue, 10:20am	( )
October 21 Tue, 10:20am	( )
October 28 Tue, 10:20am	Patricia Klein (Texas A&M)
November 18 Tue, 10:20am	Juan Pablo Zuñiga (Pontificia Universidad Católica de Chile)
December 2 Tue, 10:20am	( )
January 13 Tue, 10:20am	( )
January 20 Tue, 10:20am	( )

See also the Arithmetic Geometry Seminar

Abstracts

(Neff): Given a nodal genus one curve and a proper subcurve of genus one, we will construct a contraction that collapses the subcurve to a genus one singularity. We will do this by first introducing residues for curves over local artinian rings and "twists" of these residues by tropical data from the curve, then we will use these residues to explicitly construct the contraction.

(Wang): Matroid Schubert varieties--Schubert varieties of hyperplane arrangements--serve a role in the Kazhdan-Lusztig theory of matroids analogous to that of classical Schubert varieties in geometry. These varieties carry rich combinatorial data about the underlying hyperplane arrangements. The local Euler obstruction, a key invariant introduced by MacPherson in his definition of Chern classes for singular varieties, captures local information of the singularity. In this talk, we study the local Euler obstruction of matroid Schubert varieties and demonstrate that it is a combinatorial invariant: specifically, it equals the evaluation of the characteristic polynomial at 2.

(Ma):

(Klein):

(Zuñiga):