expository notes, essays, and paper-reading notes on computer science and mathematics. Expository Notes: Worst-Case Linear-Time Selection: The Median-of-Medians Method Why Comparison-Based Sorting has an Ω(n log n) Lower Bound Expected Number of Comparisons in Randomized Quicksort Why Building a Binary Heap Takes Linear Time The Theory of Graph Minors Expository Essays: You’re Not Cleared to Read This (Unless You Understand Lattices) Are Computers Really Random? How to Prove You Know the Secret Without Telling the Secret? Why do Black Holes and Blockchain Use the Same Math? Pi vs. AI: Could a Neural Network Predict the Next Digit of Pi? Paper Notes: