Articles
Probability
Eight Ways to Derive the Characteristic Function of the Normal Distribution

A Simple Probabilistic Proof of a Wallis-type Formula for the Gamma Function

The Strong Law of Large Numbers without Recycling

A Relatively Simple and Elementary Proof of the Baum—Katz Theorem

A Rigorous Treatment of a Fundamental Result in Self-similar Traffic Modeling

An Elementary Exposition on the Proof of the Hartman—Wintner Law of Iterated Logarithm

Exchangeability and Moment Problems

Simple Proofs of the Kolmogorov Extension Theorem and Prokhorovs' Theorem

Real Analysis
An Intuitive Proof of the Hahn—Kolmogorov Theorem

A Proof of Hölder's Inequality using the Layer Cake Representation

Proving Integral Convergence Theorems by Viewing Integrals as Areas

Comparison of the Powers of Convergence Theorems for Integrals

Set Theory
Borel's Proof of the Heine—Borel Theorem

Perturbing All Points in R^d into a General Position

A Note on the Axiom of Choice

Topology
Characterization of Continuous Maps in terms of Preservation of Connected Sets

An Application of Complete Metric Space Theory: the Picard—Lindelöf Theorem

Filters in General Topology

Countable Products of Finite Spaces

An Application of Ascoli's Theorem: the Cauchy—Peano Existence Theorem

Algebra
A Short and Self-contained Proof of the Insolvability of the Quintic by Radicals

An Overkill Proof of Wilson's Theorem using a Sylow Theorem

A Linear-algebraic Overkill Proof that Finite Fields are not Algebraically Closed

LaTeX
I gave a 3-hour introductory lecture on LaTeX for KAIST students in Korean on May 16th, 2021. Click here for the video recording of the lecture. Please download intro_to_latex_210516 before attending the lecture. You can find answers to the exercises in after_lecture.