Ian Chen

Ian Chen

Undergraduate

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A list of all the posts and pages found on the site. For you robots out there, there is an XML version available for digesting as well.

Pages

Posts

2026 July Mindbenders

9 minute read

Published:

If you roll six dice, you could get the same number on every die, or (in contrast) all different numbers. What is the probability of getting exactly four distinct numbers? source.

Cycle Analysis

9 minute read

Published:

Consider an infinitely long sequence of coin flips, i.e. with \(p\) probability heads and \(1-p\) probability tails. You get points for non-overlapping pairs of consecutive heads. How many points do you expect to obtain per flip? That is, what is the limit for the ratio of the number of points over number of flips?

2026 January Momath Mindbender

3 minute read

Published:

Puzzle from here. Consider a ladybug starting on the 12-hand of the clock. During each timestep, it will choose to walk either counterclockwise or clockwise, each with 50% probability. What is the probability that the last new number it visits is 6?

Reinforcement Learning

less than 1 minute read

Published:

Over a year ago now, I took some notes on reinforcement learning from a series of lectures availabe on YouTube. They can be found here.

notes

MATH 427: Abstract Algebra

Published:

Notes for the Spring 2025 instance of honors abstract algebra at UIUC, taught by Eugene Lerman.

Mining Complex Networks

Published:

These notes very briefly summarize Chapters 2, 3, 5, 6 from Klaminski, Pralat, and Theberge’s book on Mining Complex Networks.

Reading group

Published:

Schedule for Readings with Kyle Enkzhul and Tai Nguyen

portfolio

publications

Dense Subgraph Clustering and a New Cluster Ensemble Method

Published in Complex Networks and Applications, 2025

Dense Subgraph Clustering and a New Cluster Ensemble Method

Recommended citation: Vu-Le, The-Anh and Lamy, Joao Alfredo Cardoso Lamy and Alessi, Tomas and Chen, Ian and Park, Minhyuk and Harb, Elfarouk and Chacko, George and Warnow, Tandy. (2025). "Dense Subgraph Clustering and a New Cluster Ensemble Method&quot
Download Paper | Download Bibtex

talks

DeBruijn Graphs

Published:

Elementary graph theory, De Bruijn sequences, and genome assembly…

Recommended citation: Chen, Ian; De Bruijn Graphs
Download Slides

Dynamic Graph Connectivity

Published:

In a static graph, checking whether nodes are in the connected component takes linear time. I will describe the Kapron, King, Mountjoy algorithm supporting polylog time updates and queries.

Recommended citation: Chen, Ian; Dynamic Graph Connectivity
Download Slides

Parallel Connectivity and Shortest Paths

Published:

Near-linear work algorithms for connectivity and single-source shortest paths (SSSP) have been known since before the 1950s. In this talk, we will describe approaches to increase their parallelism, including coarsening algorithms for connectivity, and incremental stepping algorithms for SSSP.

Recommended citation: Chen, Ian; Parallel Connectivity and Shortests Paths
Download Slides

teaching

CS 233 Computer Architecture

Undergraduate course, University of Illinois Urbana-Champaign, Siebel School of Computing and Data Science, 2024

Undergraduate course assistant in Fall 2024 and Spring 2025.

CS 473 Algorithms

Undergraduate/Graduate course, University of Illinois Urbana-Champaign, Siebel School of Computing and Data Science, 2025

Undergraduate course assistant in Fall 2025.