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Spring 2026
Welcome to the Topology and Geometry Seminar at IISER Kolkata! Our seminars focus on the latest developments and cutting-edge research in topology and geometry, as well as related areas of mathematics. Seminars are open to all and may be held offline or online. While there is no fixed schedule, please check back frequently for updates. Join mailing group (or if you want to give a talk) for the latest seminar schedule and format updates. Stay connected with our community and don't miss out on exciting events. Thank you for your interest in the Topology and Geometry Seminar at IISER Kolkata! An archive of previous talks can be found in the following links: Spring 2023, Autumn 2023, Spring 2024, Autumn 2024, Spring 2025, Autumn 2025.
Upcoming Talks
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(tentative) Traces in assembler K-theory
Ramyak Bilas (Indiana University, USA)TBA
Venue: Zoom link [TBA]
Time: 7:30-8:30 pm IST (3rd and 5th March 2026)
8-9 am IST (9th March 2026)
Previous Talks
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Uniqueness in the local Donaldson-Scaduto conjecture
Gorapada Bera (Simons center for Geometry & Physics, NY, USA)Donaldson’s program on the adiabatic limit of $K3-$fibered $G_2-$manifolds relates associative submanifolds to certain weighted trivalent graphs on the base called gradient cycles. A key ingredient in this relation, near a trivalent vertex, is the existence and uniqueness of an associative pair of pants in the $G_2-$manifold formed as a product of a $K3$ surface and the Euclidean $3-$plane. This is known as the Donaldson–Scaduto conjecture. Although this conjecture remains open, a local version replacing the $K3$ surface with an ALE or ALF hyperkähler $4-$manifold of type $A_2$, has been shown to exist by Esfahani and Li. In this talk, I will discuss our joint work on proving the uniqueness, showing that no other associative pair of pants satisfies this local version of the conjecture.
Venue: LHC G09, IISER Kolkata
Time: 3 PM IST
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Rational homotopy theory and algebraic models
Jiawei Zhou (Nanchang University, China)Rational homotopy theory studies the free parts of homotopy and homology groups. By ignoring torsion, the remaining structure can be represented by algebraic models. This approach works particularly well for simply connected spaces with cohomology of finite type. The Sullivan model, a special type of differentially graded algebra, is one of the central algebraic models in rational homotopy theory. In this lecture series, I will introduce the construction of the Sullivan model, explain how it encodes topological information, and describe how to reconstruct a space from such an algebra. My current research focuses on understanding when the realization of a non-simply-connected Sullivan algebra preserves cohomology. If time permits, I will also discuss another related topic: a space is called formal if its rational cohomology ring itself can serve as its algebraic model. Although a sphere bundle over a compact formal manifold may not be formal, its formality can be determined arithmetically using the Bianchi-Massey tensor introduced by Crowley and Nordström.