Chenlin‘s Blog

In our last project, we use Dini's lemma in one step of proof. This result, although should be part of undergraduate analysis, is really...

There is a long time that I have not updated my blog. This time, I would like to talk about once again a question in Alibaba competitio...

I would like to record one theorem learned in the Alibaba competition this year. In fact, this problem has also appeared in the maths compet...

Today I am asked a high school level question: given $1 \geq p_1 \geq p_2 \cdots p_n \geq 0$ and find a subset of these number such that ...

This week I heard a very nice talk from my classmate Huajie Qian. The question can be stated as doing $\min_{x}c \cdot x$ under the constrai...

This is a question about the correlation. Let $X,Y$ be two Gaussion random variable $\mathcal{N}(0,1)$ with correlation $\beta$, then prove ...

The strong Markov property for Brownian motion is well known and it is also naturally true for the Brownian Bridge. In fact, since Brownian ...