Posts by

Xing Shi Cai


Tiling chessboard with L-shaped tiles

I created a Jupyter notebook for teaching induction in combinatorics to demonstrate that you can always tile a \(2^n …




RandomTree.jl -- Simulation on large random trees with Julia

I have been working on a software package RandomTree.jl that could effectively generate pretty large (\(10^8\) nodes) random …




Combinatorics 1MA020, Spring 2019 (Archive)

I just finished teaching the course Combinatorics 1MA020 (Spring 2019) at Uppsala University. Here are the materials that I prepared …




The joy of experimental mathematics

I came across an interesting identity on math.stackexchange.com.




The sum of n uniform [0,1] random variables

Update: Svante Janson told me yesterday that the integral I had at the end of this post is known as …




An example of proving summation identities with computer

I am trying to learn how to use computers to prove identities like this one




The Strahler-Horton number on random trees

We list some open problems regarding the Strahler-Horton number on random trees \(T_n\).




The moment of truncated random variables

Given a random variable \(Y\), sometimes we want to compute the expectation of \(Y[Y\le a]\), where \([P]=1 …




The Convexity Property Related to Beta Densities -- In sage

This is a continuation of my previous post on beta distribution.

My colleague Tilo wants me to use Sagemath instead …




Another version of Chernoff's bound and a Mathematica package for it

Chernoff's bound is a group of quite well-known concentration-inequalities. I though I know it but last week my collage Gabriel …