Seminars and Colloquia by Series

TBD by Kisun Lee

Series
Algebra Seminar
Time
Monday, December 4, 2023 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Kisun Lee – Clemson University

TBD by Chiara Meroni

Series
Algebra Seminar
Time
Monday, November 27, 2023 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Chiara Meroni – Harvard John A. Paulson School of Engineering and Applied Sciences

TBD by Austin Conner

Series
Algebra Seminar
Time
Monday, November 20, 2023 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Austin Conner – Harvard University

TBD by Kiumars Kaveh

Series
Algebra Seminar
Time
Monday, November 13, 2023 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Kiumars Kaveh – University of Pittsburgh

Combinatorial commutative algebra rules

Series
Algebra Seminar
Time
Monday, October 16, 2023 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Ada Stelzer – University of Illinois Urbana-Champaign –

Please Note: There will be a pre-seminar (aimed toward grad students and postdocs) from 11:00 am-11:30 am in Skiles 006.

We present an algorithm that generates sets of size equal to the degree of a given projective variety. The steps of this "CCAR" algorithm are individually well-known, but we argue that when combined they form a versatile and under-used method for studying problems in computational algebraic geometry. The latter part of the talk will focus on applying the CCAR algorithm to examples from Schubert calculus.

A stronger Torelli theorem for graphs

Series
Algebra Seminar
Time
Monday, October 2, 2023 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Sarah Griffith – Brown University –

Please Note: There will be a pre-seminar (aimed toward grad students and postdocs) from 11:00 am-11:30 am in Skiles 006.

Recent research trends have explored curious analogies between the theory of graphs and Riemann surfaces. To each graph we can associate a real metric torus, known as its Jacobian. It was previously known that isomorphisms of graph Jacobians yield isomorphisms of the associated graphic matroids, partially mirroring a classical algebraic geometry result known as the Torelli theorem. However, the result on graphs is not as strong as a direct analogue of the Riemann surface result would be, nor does it use as much data. I will discuss how the graph Torelli theorem can be refined to incorporate additional data as with Riemann surfaces, in which case it produces isomorphisms of graphs. If time permits, I will describe further recent work in this direction.

Filtrations of tope spaces of oriented matroids

Series
Algebra Seminar
Time
Monday, September 25, 2023 - 13:00 for 1 hour (actually 50 minutes)
Location
Skiles 006
Speaker
Chi Ho Yuen – Oslo University –

Please Note: There will be a pre-seminar (aimed toward grad students and postdocs) from 11:00 am-11:30 am in Skiles 006.

Oriented matroids are matroids with extra sign data, and they are useful in the tropical study of real algebraic geometry. In order to study the topology of real algebraic hypersurfaces constructed from patchworking, Renaudineau and Shaw introduced an algebraically defined filtration of the tope space of an oriented matroid based on Quillen filtration. We will prove the equality between their filtration (together with the induced maps), the topologically defined Kalinin filtration, and the combinatorially defined Varchenko-Gelfand dual degree filtration over Z/2Z. We will also explain how the dual degree filtration can serve as a Z-coefficient version of the other two in this setting. This is joint work with Kris Shaw.

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