"Inspired" by Chai and Why :)
It was one fine morning at Prithvi Theatre in Juhu, during the monthly Chai and Why talk on counting symmetries, organized by the charismatic Arnab Bhattacharya and the wonderful chai and why team, that this idea originated: why not blatantly copy this and try something eerily similar at IIT Bombay? And here we are!
The Department of Industrial Engineering and Operations Research at IIT Bombay is happy and excited about welcoming you to our pedagogical talk series "stORIEs and snacks" primarily focusing on the genesis of ideas and elementary inspirations to motivate subject matters. This talk series, started in August 2024, originated with the advent of our undergraduate program to invigorate and inspire young minds. We look forward to hosting you at our upcoming talks!
Upcoming Talk
Date: Wednesday, October 28, 2026
Time: 5:30 PM (snacks first, stories next)
Venue: LH 101 (Lecture Hall Complex)
Title: When Many Wrongs Make (Almost) a Right
Speaker: Vishnu Narayanan, Department of Industrial Engg and Operations Research, IIT Bombay
Abstract: You can't take half a course, buy a third of a car, or send part of a data packet. Many real-life choices are all-or-nothing, and that makes them hard to work with mathematically. But something surprising happens when lots of people make these lumpy choices at once: the combined result starts to behave as if everything could be split smoothly. This idea is captured by the Shapley–Folkman theorem, a beautiful result about what happens when you add up many "bumpy" shapes: the more you add, the closer the total gets to a nice, smooth one. We'll build intuition for this through simple pictures and examples, then see it in action, from fairly assigning seats in popular university courses to judging how good our solutions are when managing congested networks. No advanced background is needed, just curiosity!
RSVP: Here
Calendar invite: 
Past Talks
Date: Wednesday, September 30, 2026
Time: 5:30 PM (snacks first, stories next)
Venue: LA 202 (Lecture Hall Complex)
Title: A Tall Tale of Two Tails: Tête-à-tête with Branching Random Walks in the Long Run
Speaker: Parthanil Roy, Department of Mathematics, IIT Bombay
Abstract: Random walks are simple mathematical models for describing how something moves when each step involves an element of chance. They appear in many areas, from physics and biology to finance, networks, and computer science. What happens if the walkers can also reproduce, so that one particle becomes two, then four, and eventually a large population? This leads to a branching random walk - a simple model that combines random movement with growth. In this talk, aimed at students from all disciplines, we will explore a natural question: after the system has been running for a very long time, how far can the most advanced particles travel? We shall see how a surprisingly rich mathematical picture emerges from this simple idea.
Brief Bio of the Speaker: Parthanil Roy is a Professor in the Department of Mathematics at IIT Bombay, with research interests spanning probabilistic aspects of heavy-tailed phenomena, stable processes, long-range dependence, branching random walks, and random walks with memory. In addition to his research and academic responsibilities, Prof. Roy has been actively involved in outreach initiatives aimed at popularizing mathematics and statistics among students and wider communities.
Date: Wednesday, August 12, 2026
Time: 6:00 PM (snacks first, stories next)
Venue: LC 201 (Lecture Hall Complex)
Title: Approximations
Speaker: Piyush Srivastava, Tata Institute of Fundamental Research
Abstract: It is famously hard to find "exact" answers. So we often settle for approximate ones. But how approximate is still "good"? And how do we get the "best" approximations? In this talk, we will explore some glimpses from the fascinating theory and practice of mathematical approximation: starting from ancient usages in carpentry, land measurement, and observational astronomy, to modern mathematics and machine learning.
Brief Bio of the Speaker: Piyush Srivastava works at the School of Technology and Computer Science at the Tata Institute of Fundamental Research. He is interested in algorithms, probability, and their interactions with physics.
Date: Thursday, October 16, 2025
Time: 5:00 PM (snacks first, stories next)
Venue: VMCC-31 (Victor Menzes Convention Center)
Title: From card tricks to the Mandelbrot set
Speaker: Ramprasad Saptharishi, School of Technology and Computer Science, TIFR Mumbai
Abstract: The Mandelbrot set is an interesting subset of the complex numbers that arise from a very simple-to-state iterative process on the complex numbers. With that as an excuse, let us explore some card tricks! Card tricks based on mathematical ideas often have a reputation of being boring, but people who say so haven't seen the Gilbreath Principle. The point of this talk will be to explore this principle (named after Norman Gilbreath) that forms the backbone of several astonishing effects. We will see a few card tricks, try and reconstruct the method, and prove some simple and interesting properties of these `Gilbreath permutations'. Also, it turns out that Gilbreath permutations have some interesting connections to the Mandelbrot set. But all this is just an excuse for a deeper message.
Bio: Ramprasad Saptharishi is a faculty member at the School of Technology and Computer Science at the Tata Institute of Fundamental Research Mumbai. Prior to joining TIFR, he obtained his PhD from Chennai Mathematical and postdoc stints at Microsoft Research India and Tel Aviv University. When he is not playing board games, or practicing card tricks, he spends time pondering about computational questions with an algebraic flavour.
Date: Wednesday, April 16, 2025
Time: 5:00 PM (snacks first, stories next)
Venue: IC-1 (SJSOM Ground Floor)
Title: Some Stories about Scientists - from Archimedes to Einstein : True or False ?
Speaker: SD Agashe, Retired - Department of Electrical Engineering, IIT Bombay
Abstract: We will examine some of the stories about scientists, often repeated in College textbooks, to look at their background, and try to see what is fact and what is fable ! My story about these stories will be supported by some evidence.
Date: Tuesday, March 25, 2025
Time: 5:00 PM (snacks first, stories next)
Venue: EEG-301 (Third Floor, Girish Gaitonde Building)
Title: On Finite Simple Groups
Speaker: NS Narasimha Sastry, Retired - Department of Mathematics, ISI Bangalore
Abstract: In this talk, I try to (very) briefly describe the list of finite simple groups; the mathematical structures they are the symmetries of; some easily statable, but crucial, initial insights that started the classification; some consequences of the classification; and some indication of the marvels of the monster simple group and its connection to modular forms and the affine E_8 root system. Given the enormity of the topic, I will concentrate on easily accessible, but significant, aspects of the topic.
Date: Thursday, February 13, 2025
Time: 5:00 PM (snacks first, stories next)
Venue: LH-301 (Lecture Hall Complex)
Title: The Ubiquity of Lie Groups and their Applications
Speaker: Ravi N Banavar, Systems and Control Engineering, IIT Bombay
Abstract: The comfort zone of most engineers is the Euclidean space. Most applications rely on tools from the repository of this space - transforms, projections, norms and inner products. However, the intrinsic nature or setting of many problems in engineering is not in this domain. (An example is the orientation control of a satellite or a rigid body.) As a result, the solutions that have been proposed for such problems by using a Euclidean setting, are necessarily "local" and termed "coordinate-dependant." This weakness has beckoned new paradigms. Stepping not too far from the comfort zone of a Euclidean space, we encounter an object called a Lie Group. The umbilical connection of a Lie group to a Lie algebra (a vector space) brings in familiarity to the newbie in terms of many tools commonly employed in a Euclidean space. In this talk I shall present the preliminary machinery for Lie groups, and four domains of applications - multiagent control, consensus, optimal control and observer design
Date: Thursday, October 10, 2024
Time: 5:05 PM (snacks first, stories next)
Venue: LC 301 (Lecture Hall Complex)
Title: The Traveling Salesman, his crew and some last mile roadblocks
Speaker: Arvind Kumar, Senior Advisor, Optym
Abstract: The traveling salesman problem is one of the most celebrated OR problems specifically seeking an answer to the question, "Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the origin city?" Now how about doing the same if you had a crew? Divide and conquer? This specific story will take you through the journey of this problem along with its more contemporary generalisations in the form of the Vehicle Routing problem (VRP) and some new insights using neighbourhood search algorithms for optimizing last mile deliveries
Date: Wednesday, September 04, 2024
Time: 5:05 PM (snacks first, stories next)
Venue: LH-102 (Lecture Hall Complex)
Title: Understanding Symmetries
Speaker: Radhika Gupta, School of Mathematics, Tata Institute of Fundamental Research
Abstract: Integers, real numbers, reading a clock, petals of a flower, braids, tiling of the plane, rubik's cube, wallpaper patterns, rotations of the plane, permutations of a finite set. Is this a random list? Or is there a pattern hidden somewhere?! We will explore some of these objects and discover the underlying theme of the mathematical concept called 'groups' tying them all together. The search for symmetry is one of the biggest adventures in mathematics and the goal of this talk is to help you get started on yours.