Random

technology, observations, and reflection

Some combinatorial graph problems that have an algebraic answer

all answers have something to do with eigenvalues

10 min read · February 23, 2026 · authored by Jie Chen

2026 · math
Some facts about random orthonormal vectors and matrices

without prerequisite knowledge of the Haar measure

5 min read · February 20, 2026 · authored by Jie Chen

2026 · probability
The exponential of ... everything?

how far can we use the Taylor series to define the exponential?

14 min read · February 12, 2026 · authored by Jie Chen

2026 · math quantum
How to get the sorted array and indices in Python without importing additional modules like Numpy

the power of lambda functions

2 min read · January 24, 2026 · authored by Jie Chen

2026 · code
A subtly wrong proof that ChatGPT generated

and a counter example provided by the same ChatGPT

7 min read · January 21, 2026 · authored by Jie Chen

2026 · math AI