Chennai Mathematical Institute
Seminars




Today's Seminar
  • 02-02-26
    Lecture series announcement
    The dates of his lectures are:
    Lectures 1 and 2 will be on January 16 at 3:30 p.m. Both talks will be 45 minutes long, with a short break.
    Lectures 3 and 4 will be on January 27 and 29 from 3:30 p.m. to 4.30 p.m.
    Lectures 5 and 6 will be on February 2 and 3 from 3:30 p.m. to 4.30 p.m.
    Venue: Seminar Hall, CMI (hybrid mode)
    Actions of finite group schemes
    Michel Brion
    Institut Fourier at the UniversitE Grenoble Alpes, France.
    Abstract
    Finite group schemes play an important role in the structure and actions of algebraic groups over a field of positive characteristics. The talks will first present general results on finite group schemes, their (rational) actions and their fields of invariants. Then they will focus on equivariant versions of the classical notions of normality and regularity, which remedy the failure of equivariant desingularization in the setting of actions of infinitesimal group schemes. Equivariantly normal curves will be considered in detail, with versions of the Hurwitz and Chevalley-Weil formulas in the above setting.


Today's Seminar
  • 02-02-26
    Lecture series announcement
    Dates: 27, 28, 30 January and 2 & 4 February 2026
    Time: 3.45 to 4.45 PM
    Venue: NKN Hall (hybrid mode)
    Mock modularity of Calabi-Yau threefolds and BPS black holes
    Sergey Alexandrov
    Laboratoire Charles Coulomb and University of Montpellier, CNRS, France.
    Abstract
    This series of lectures aims to explain remarkable (mock) modular properties of generating functions of certain BPS indices which, on the one hand, coincide with generalized Donaldson-Thomas invariants of Calabi-Yau (CY) threefolds and, on the other hand, count the entropy of supersymmetric black holes appearing in compactifications of Type II string theory on these manifolds. These properties can be used to explicitly compute the generating functions up to a finite number of parameters. In the case of non-compact CYs, this has led to a complete solution of Vafa-Witten theory on rational surfaces. In the case of compact CYs, an approach to fix the ambiguity has been developed for a set of one-parameter threefolds. It relies on wall-crossing and solution of topological string by the direct integration method. I'll explain how the resulting generating functions allow to overcome the limitations of this method and find new Gromov-Witten invariants inaccessible by other means.


Today's Seminar
  • 02-02-26
    Physics Seminar
    Date: Monday, 2 February 2026
    Venue: Lecture Hall 6
    Time: 11.00 a.m. to 1.00 p.m
    String Compactifications And Cosmological Solutions, GKP Geometric Moduli
    Ratul Mahanta
    USTC, Hefei.
    Abstract
    In this seminar, I will discuss recent progress in developing top-down models within type IIB superstring compactifications. Two aspects will be discussed. In the first part, I will discuss construction of 10D type IIB supergravity solutions featuring a time-dependent 4D spacetime component, and present an extension of Maldacena Nunez (no-)go analysis. In the second part, I will discuss the geometric moduli space of Giddings-Kachru-Polchinski (GKP) compactifications, and present results [moduli space metric] derived for the 4D low-energy effective theory of these moduli from 10D equations of motion. I will end by discussing some open problems [including: realistic cosmology, tadpole conjecture, de Sitter construction, 4-graviton amplitude] related to the above discussion. The talk will be based on: 2512.19793, 2501.08623.


Today's Seminar
  • 02-02-26
    Lecture Announcement
    Date: Monday, 2 February 2026
    Time: 2.00 p.m.
    Venue: Seminar Hall
    On Proper Descent of Smooth Affine Surfaces with Finite Homotopy Rank-Sum
    Buddhadev Hajra
    ISI Kolkata.
    Abstract
    A classical result of J.-P. Serre shows that if there is a finite surjective morphism between normal complex algebraic varieties and the fundamental group of the source is finite, then the fundamental group of the target is also finite. This naturally leads to a higher-homotopical analogue: in the same setting, does finiteness of the second homotopy group of the source imply finiteness of the second homotopy group of the target?

    In this talk, we explain how this question is equivalent to the proper descent of the Eilenberg-MacLane property for smooth affine or projective surfaces. We present an explicit example illustrating that this descent property fails in general. Nevertheless, we introduce a weaker notion, called the finite homotopy rank-sum property, and explain why this property can be expected to descend under proper morphisms of smooth affine surfaces.


Forthcoming Seminars
  • 03-02-26
    Lecture Series on Social Choice Theory
    Lectures 1 and 2: Tuesday, 3 February 2026, from 10:30 a.m. to 1:05 p.m.
    Lectures 3 and 4: Tuesday, 10 February 2026, from 10:30 a.m. to 1:05 p.m.
    Venue: Lecture Hall 801
    Lecture Series on Social Choice Theory
    Ori Livson
    University of Sydney.

  • 03-02-26
    Seminar Announcement
    Date: Tuesday, 3 February 2026
    Time: 2.00 to 3:30 p.m.
    Venue: Lecture Hall 1
    Group Order and Group Non-Membership is in QCMA
    Dhara Thakkar
    Graduate School of Mathematics, Nagoya University.

  • 04-02-26
    Mathematics Colloquium
    Date: Wednesday, 4 February 2026
    Time: 3:30 pm
    Venue: Seminar Hall
    Convergence of varieties and (plethystic) Euler products
    Ronno Das
    Lodha Mathematical Sciences Institute.

  • 06-02-26
    Seminar Announcement
    Date: Friday, 06 February 2026
    Time: 3.30 p.m.
    Venue: Seminar Hall
    q-opers, QQ-systems and Bethe Ansatz for spin chains
    Rahul Singh
    YMSC, Tsinghua University.

  • 26-02-26
    Lecture Announcement
    Date Thursday, 26 February 2026
    Time: 3:30 p.m.
    Venue: Seminar Hall
    Scaling of multidimensional matrices and their applications
    T E S Raghavan
    Dept. of Math, Stat and computer Science, University of Illinois at Chicago.

Past Seminars (this year)
  • 30-01-26
    Physics Seminar
    Date: Friday, 30 January 2026
    Time: 11:45 a.m.
    Venue: Seminar Hall
    LIGO-India and the future of Gravitational Wave Astronomy
    Sanjit Mitra
    IUCAA, Pune.

  • 28-01-26
    Seminar Announcement
    Date: Wednesday, 28 January 2026
    Time: 3.30 to 4.30 p.m.
    Venue: Seminar Hall
    Some early Ramsey type theorems and some applications
    S. D. Adhikari
    RKMVERI.

  • 23-01-26
    Physics Seminar
    Date: Friday, 23 January 2026
    Time: 10.30 a.m. to 11.30 a.m.
    Venue: Lecture Hall 6
    Emergent Higher-Spin Symmetry on the Celestial Sphere from Loop-Corrected Soft Photon Theorems
    Biswajit Sahoo
    Kings College, London.

  • 22-01-26
    Physics Seminar
    Date: Thursday, 22 January 2026
    Venue: Lecture Hall 2
    Time: 1.30 p.m to 2.45 p.m.
    Modeling the gravitational-wave memory for coalescing compact binaries
    Marc Favata
    Montclair State University, USA.

  • 16-01-26
    Data Science Seminar
    Date: Friday, 16 January 2026
    Time: 2:00 p.m.
    Venue: NKN Hall
    Small Language Models: Design, Fine-Tuning and Deployment
    Sudhir Kumar
    Coriolis Technologies.

  • 16-01-26
    Seminar Announcement
    Date: Friday, 16 January 2026
    Time: 11.45 a.m.
    Venue: Seminar Hall
    Class groups of Kummer extensions associated to CM Elliptic curves
    Arindam Bhattacharya
    University of Massachusetts, Amherst.

  • 16-01-26
    Seminar Announcement
    Date: Friday, 16 January 2026
    Time: 11.45 a.m
    Venue: Lecture Hall 1
    A new characterization of VNP via Colored Determinant
    Prasad Chaugule
    IIT Delhi.

  • 13-01-26
    Seminar Announcement
    Date: Tuesday, 13 January 2026
    Time: 12:00 p.m
    Venue: Lecture Hall 4
    On the relative power of reduction notions in different characteristics
    Prasad Chaugule
    IIT Delhi.

  • 13-01-26
    Physics Seminar
    Date: Tuesday, 13 January 2026
    Time: 3:45 p.m.
    Venue: Lecture Hall 6
    Mock Modular forms and Vafa Witten Theory
    Aradhita Chattopadhyaya
    Chennai Mathematical Institute.

  • 12-01-26
    Physics Seminar
    Date: Monday, 12 January 2026
    Time: 3:45 p.m.
    Venue: Lecture Hall 6
    Mock Modular forms and Vafa Witten Theory
    Aradhita Chattopadhyaya
    Chennai Mathematical Institute.

  • 12-01-26
    Physics Seminar
    Date: Monday, 12 January 2026
    Time: 11.00 am to 1.00 p.m.
    Venue: Lecture Hall 6
    Boundary Energy-Momentum Tensors for Asymptotically Flat Spacetimes
    Vijay Nenmeli
    University of Edinburgh.

  • 09-01-26
    Computer Science Seminar
    Date: Friday, 9 January 2026
    Time: 2.00 - 3.15 p.m.
    Venue: Seminar Hall
    The complexity of the factors of polynomials
    Somnath Bhattacharjee
    University of Toronto.

  • 07-01-26
    Lecture Announcement
    Date: Wednesday, 7 January 2026
    Time: 4:00 p.m. - 4:30 p.m.
    Venue: Seminar Hall
    A Torelli type theorem for elliptic curves
    Tomasz Szemberg
    University of the National Education Commission, Krakow, Poland.

  • 07-01-26
    Lecture Announcement
    Date: Wednesday, 7 January 2026
    Time: 3:30 - 4:00 p.m.
    Venue: Seminar Hall
    Configurations of points in projective space and their projections
    Justyna Szpond
    University of the National Education Commission, Krakow, Poland.

  • 06-01-26
    Seminar Announcement
    Date: Tuesday, 6 January 2026
    Time: 2.00 to 3.30 p.m.
    Venue: Seminar Hall
    Redundancy is all you need (for CSP sparsification)
    Venkatesan Guruswami
    UC Berkeley and Simons Institute.

  • 05-01-26
    Seminar Announcement
    Date: Monday, 5 January 2026
    Time: 2.00 to 3.30 p.m.
    Venue: Seminar Hall
    Optimal Proximity Gaps for Subspace-Design Codes and (Random) Reed-Solomon Code\ s
    Rohan Goyal
    MIT.

  • 05-01-26
    Mathematics Seminar
    Date: Monday, 5 January 2026
    Time: 3.30 to 4.30 p.m.
    Venue: Seminar Hall
    The inverse system of Gorenstein points
    Maria Evelina Rossi
    University of Genoa.