Calendar

The CMSA will be hosting a Workshop on Global Categorical Symmetries from April 29–May 3, 2024.

Organizers:

Dan Freed (Harvard CMSA & Math)
Constantin Teleman  (UC Berkeley)

Participation in the workshop is by invitation.

Since the work of Jacobi and Siegel, it is well known that Theta series of quadratic lattices produce modular forms. In a vast generalization, Kudla and Millson have proved that the generating series of special cycles in orthogonal and unitary Shimura varieties are modular forms. In this talk, I will explain an extension of these results to toroidal compactifications where we prove that the generating series of divisors is a mixed mock modular form. This recovers and refines earlier results of Bruinier and Zemel. The results of this talk are joint work with Philip Engel and François Greer.

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For more info, see https://ashvin-swaminathan.github.io/home/NTSeminar.html

See webpage for more details: https://people.math.harvard.edu/~ctm/sem/

Toric matroid bundles are combinatorial objects which serve as a tropical analogue to vector bundles over toric varieties.   I’ll explain how to construct toric matroid bundles, how to check if a toric matroid bundle is globally generated or ample, and how to compute the characteristic classes of a toric matroid bundle in the T-equivariant chow cohomology of the base.  Finally, I’ll show that each matroid determines a tautological toric matroid bundle over the permutahedral toric variety.  I’ll discuss some properties of these bundles, and I’ll show that the characteristic classes of the tautological toric matroid bundle recover the tautological classes of matroids used by Berget, Eur, Spink, and Tseng to prove log-concavity properties of the Tutte polynomial.

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For more info, see https://math.mit.edu/combin/

The CMSA will be hosting a Workshop on Global Categorical Symmetries from April 29–May 3, 2024.

Organizers:

Dan Freed (Harvard CMSA & Math)
Constantin Teleman  (UC Berkeley)

Participation in the workshop is by invitation.