Following the public lecture, LMSI will host an intensive three-day workshop centered on the theme of High Dimensional Expanders (HDX).
Alex Lubotzky was a Plenary speaker on High Dimensional Expanders at the International Congress of Mathematicians 2018 Rio de Janeiro and has subsequently delivered mini- courses on the theme in the Minerva lectures at Princeton (2023) and as Simons Distinguished Visiting Professor at MIT (2025), bringing together strands in pure mathematics and theoretical computer science.
This workshop, featuring a distinguished lecture series by Professor Lubotzky and supplementary talks by leading researchers, is designed for PhD students, postdoctoral fellows, and faculty. Applications will be reviewed, and attendance is by invitation.
Abstract:
Expander graphs have been an intensive topic of research in math and CS during the last six decades. In the last two decades a high dimensional theory has emerged with (very different) applications in math & CS. In this educational workshop we present some aspects of the theory of High Dimensional Expanders (HDX) and its applications, and suggestions for further research.
|
Tuesday
23rd Dec
2025
|
9:30 AM – 10:00 AM |
Tea / Coffee |
|---|---|---|
|
10:00 AM – 11:00 AM |
Arghya MandalKazhdan Property (T), expanders, property (τ) |
|
|
11:00 AM – 11:30 AM |
Break |
|
|
11:30 AM – 12:30 PM |
Sandeep VarmaSelberg theorem, Ramanujan conjecture (a representation theoretic approach) |
|
|
12:30 PM – 1:30 PM |
Lunch |
|
|
1:30 PM – 2:30 PM |
Radhika GuptaThe Bruhat-Tits tree of SL₂(ℚₚ) and the arithmetic lattice based on the Hamilton quaternions |
|
|
2:30 PM – 3:30 PM |
Gaurav AggarwalThe Bruhat-Tits tree of SL₂(ℚₚ) and the arithmetic lattice based on the Hamilton quaternions |
|
|
3:30 PM – 4:00 PM |
Break |
|
|
4:00 PM – 5:00 PM |
Alex LubotzkyFrom Ramanujan graphs to Ramanujan Complexes |
|
Wednesday
24th Dec
2025
|
9.30 AM - 10.00 AM |
Tea/Coffee |
|---|---|---|
10.00 AM - 11.00 AM |
Subhadip DeyBruhat-Tits buildings |
|
11.00 AM - 11.30 AM |
Break |
|
11.30 AM - 12.30 PM |
Subhadip DeyArithmetic lattice in PGLd(F) |
|
12.30 PM - 1.30 PM |
Lunch |
|
1.30 PM - 2.30 PM |
Bharatram RangarajanRamanujan complexes |
|
2.30 PM - 3.30 PM |
Break |
|
3.30 PM - 4.30 PM |
Alex LubotzkyGeometric and topological expanders |
|
Thursday
25th Dec
2025
|
9.30 AM - 10.00 AM |
Tea/Coffee |
|---|---|---|
10.00 AM - 11.00 AM |
Radhika GanapathySpectral gap, cohomology over ℝ, Garland theory |
|
11.00 AM - 11.30 AM |
Break |
|
11.30 AM - 12.30 PM |
Balarka Sen𝔽₂-cohomology, coboundary expanders, and topological overlapping |
|
12.30 PM - 1.30 PM |
Lunch |
|
1.30 PM - 2.30 PM |
Bharatram Rangarajan𝔽₂-cohomology and testability, cohomology with coefficients in Sym(n) |
|
2.30 PM - 3.30 PM |
Break |
|
3.30 PM - 4.30 PM |
Alex LubotzkyStability and group approximation |
To Be Updated
| Name | Affiliation/Institution |
|---|---|
| Gaurav Aggarwal | University of Zurich |
| Anirban Basak | ICTS-TIFR |
| Jatin Batra | TIFR Mumbai |
| Indranil Bhattacharyya | TIFR Mumbai |
| Subhajit Chakraborty | TIFR Mumbai |
| Ritwik Chakraborty | TIFR Mumbai |
| Soham Chatterjee | TIFR Mumbai |
| Sagnik Chatterjee | TIFR Mumbai |
| Shaivi Chavan | CUNY Graduate Center |
| Debattam Das | ISI Kolkata |
| Nishant Pratim Das | TIFR Mumbai |
| Sourav Das | TIFR Mumbai |
| Shubhabrata Das | Presidency University, Kolkata |
| Subhadip Dey | TIFR Mumbai |
| Sabyasachi Dhar | IIT Bombay |
| Mohammed Farhaan | BMS College of Engineering |
| Radhika Ganapathy | Indian Institute of Science, Bengaluru |
| S Ganguly | Indian Statistical Institute |
| Sourav Ghosh | Ashoka University |
| Anish Ghosh | TIFR Mumbai |
| Radhika Gupta | TIFR Mumbai |
| Rakesh Halder | TIFR Mumbai |
| Devadatta G. Hegde | TIFR Mumbai |
| Manan Jain | IISER Mohali |
| Subham Jaiswal | TIFR Mumbai |
| Samyak Jha | IISc Bangalore |
| MAHESH KRISHNA K | Chanakya University |
| Amith Shastri K | Plaksha University, Mohali |
| Amolak Ratan Kalra | University of Waterloo |
| Pankaj Kapari | TIFR Mumbai |
| Shambhu kumar | SOUTH Asian University |
| Shambhu kumar | IIT J |
| Nikhil Kumar | TIFR Mumbai |
| PRAVEEN KUMAR LAVUDI | Sri Sathya Sai University for Human Excellence |
| Aiswarya M | TIFR Mumbai |
| Pokharanakar Mugdha Mahesh | IISER Bhopal |
| Kummari Mallesham | IIT Bombay |
| Arghya Mandal | KREA University |
| Khushi Mishra | IISER Mohali |
| Dr Sanjay Mishra | Amity University Lucknow Campus |
| Debanjan Nandi | Indian Statistical Institute |
| Sundara Narasimhan | TIFR Mumbai |
| Hariharan Narayanan | TIFR Mumbai |
| Abhijit Pal | IIT-Kanpur |
| Aratrika Pandey | IIT Bombay |
| Dipendra Prasad | IIT Bombay |
| Saad Qadri | The University of Hong Kong |
| Pritika Raj | IISER Tirupati |
| C S Rajan | Ashoka University |
| Omkar Ramdas | IIT Bombay |
| Bharatram Rangarajan | UCLouvain |
| Jyoti Prakash Saha | IISER Bhopal |
| Lal Bahadur Sahu | IIT Bombay |
| Rittayan Santra | Presidency University |
| Soham Sen | IIT Kanpur |
| Balarka Sen | TIFR Mumbai |
| Hariom Sharma | IIT Bombay |
| Dwaipayan Sharma | Indian Institute of Science Education and Research, Mohali |
| Shashank Vikram Singh | IISER Mohali |
| Shrinit Singh | ICTS-TIFR Bengaluru |
| Animesh Sinha | IIT Bombay |
| Animesh Sinha | IIT Bombay |
| Piyush Srivastava | Tata Institute of Fundamental Research |
| Sandeep Varma | TIFR Mumbai |
| Mahendra Verma | IIT Roorkee |
| Maya Verma | TIFR, Mumbai |
| Vishal Kumar Yadav | Dhirubhai Ambani University, Gandhinagar, Gujarat |