COL863: Special Topics in Theoretical Computer Science
Topic: Concentration Inequalities and their Applications in Computer Science

Also listed as COL7188 for 2025 Entry students

I semester: 2025-26

Amitabha Bagchi



Class Timings: M Th 3:30PM-5PM.
Venue: LH 421

Course objectives

The purpose of this course is to discuss various inequalities that help bound the probability that a random variable, or sum of random variables, is far from its expected value. We will show how these inequalities are used in various area of computer science like algorithms, networks, and machine learning.

Topics

Background required: Elementary probability, some linear algebra.

If we have time left, and based on interest, we may also cover other topics. A dscussion of other possibilities will be held around the midpoint of the class.

Text

Other references

Course calendar

Evaluation

Evaluation will be on the basis of 4 take-home exams, each of equal weight. No in-room exams will be held for this class during the scheduled Midterm and Major exam period given in the institute calendar. Exam policies
  1. You are allowed to discuss solutions but must write them out yourself without using an AI tools to write your solution. Please give credit to your classmates where due.
  2. Latexed solutions are preferred but handwritten is acceptable. The page limit is 2 pages per solution. This has to be respected.
  3. Late submission is not allowed under any circumstances. No emailed solution will be accepted. These are mutliple day exams so there is no excuse for not submitting on time.

Attendance policy

If your attendance is below 75% at the end of the class (i.e 20 lectures or lower) your 4th take-home exam will not be graded. If your attendance in the first 14 lectures < 50% (6 lectures or lower) you will be withdrawn from the class and none of your remaining papers will be graded.

Note 1: For the purposes of the above policy, any class that has not been held or cancelled by the instructor will be counted as a "Present" for all registered students.

Note 2: Attendance will be taken at 3:35PM, i.e., 5 minutes after the scheduled beginning time for the class. If you reach after your name is called you will be marked absent. No exceptions will be made. To make this policy fair, the roll order will be randomised in each class.

Note 3: Assume that there are n students in the class and that student A's arrival time to class is a random variable X with mean 3:30pm + Y where E[Y] = k (minutes) and Var[Y] = \sigma. Assuming that calling out one student's name takes 3 seconds and that m classes are held, give a tail bound (in terms k, n, \sigma and m) that student A will fall below 75% attendance. Assume that the arrival time for each day is independent of all other arrival times. Given an arbitrary \epsilon > 0, what is the largest value of k for which the probability of A's falling below 75% attendance is at most \epsilon? A complete analysis of this will earn you 1 free attendance :-)

Plagiarism policy

If you copy even a single line from anyone else's paper or any book, website, or any other source (including AI assistants of any kind) your score for the entire course will be set to 0.

Audit policy

Audit pass will be given if
Amitabha Bagchi