Ulysses’ trip

Latest post

Mar 2, 2026, 00:07:43

I am using #Thunar as my #filemanager and #Ghostty as my #terminal. One thing that bugs me is that clicking "open terminal here" in Thunar opens Ghostty in the default working directory instead. I just fixed this today by changing the command to `TERM_PROGRAM=dumb exo-open --working-directory %f --launch TerminalEmulator`, i.e., adding an environment variable `TERM_PROGRAM`. The value does not matter, but it has to have some value for exo-open to work. No idea why.

Articles

Nov 9, 2023
Rotational symmetry of plane lattices as a simple example of algebraic number theory
For a plane lattice, there is only a finite number of different rotational symmetries that are compatible with the discrete translational symmetry. For example, the 5-fold rotational symmetry is not one of them. Why is that? It turns out that whether an $m$ -fold symmetry is compatible with translational symmetry is the same as whether $\varphi(m)\le2$ .
/math #complex #condensed matter physics #algebraic number theory #lattice #mathematical physics
Nov 6, 2023
I restructured my blog
If you have not noticed, the equations on my blog are now rendered server-side. This change makes it possible for those who turn off JavaScript on their browsers to see the equations. I also updated the theme from Minima v2 to Minima v3.
/update #jekyll #tex #update #web
Oct 31, 2023
An 🎃 easy 👻 but 🍬 spooky 💀 Ruby challenge
“It’s the weekend and you’ve just completed a seance with friends. After communing with the dead, you realize a mysterious message was left behind.” What is the decoded message? Use your Ruby skills to find out!
/programming #ruby #code golf #fooling around
Oct 18, 2023
You can replace $\mathrm i$ with $-\mathrm i$ in the Schrödinger equation?
When someone asks you why it is $-\mathrm i$ here instead of $\mathrm i$ or the other way around, you can say that this is just a convention. My professor of quantum mechanics once asked the class similar a question, and I replied with this letter.
/physics #quantum mechanics #letter #complex
Sep 29, 2023
How to self-host Overleaf (ShareLaTeX)
It has been a pain setting up Overleaf on my own server. I have finally figured it out and I am sharing my notes here.
/guide #linux #selfhosting #tex
Sep 17, 2023
My old computers and my experience of daily driving Linux and self-hosting
I have been using Linux and self-hosting for over a year now. Overall, I would like to say that it is rather satisfactory and that I will continue to use Linux as my daily driver in future. Thinking of that, I felt a little bit nostalgic about my old computers. So I decided to write an article about my old computers and my experience of daily driving Linux now.
/misc #linux #selfhosting
Sep 8, 2023
I created Sunniesnow, a rhythm game similar to Lyrica
In order to build a better player community for the rhythm game Lyrica, I created a new rhythm game called Sunniesnow. Learn more about Sunniesnow by joining our Discord server.
/update #update #rhythm game #web
May 9, 2023
The distribution when indistinguishable balls are put into boxes
Suppose there are $n$ distinguishable boxes and $k$ indistinguishable balls. Now, we randomly put the balls into the boxes. For each of the boxes, what is the probability that it contains $m$ balls? This is a simple combanitorics problem that can be solved by the stars and bars method. It turns out that in the limit $n,k\to\infty$ with $k/n$ fixed, the distribution tends to be a geometric distribution.
/math #probability #combinatorics #ruby
May 7, 2023
Labeled break, next, and redo in Ruby
Many languages support breaking out of nested loops, such as Perl, Java, JavaScript, C#, etc. Languages that have goto can also do this easily. However, in most other languages, it is not easy to break out of nested loops. I want to introduce a way to do this in Ruby.
/programming #meta programming #ruby
May 1, 2023
Free trade (single good case)
I set up a simple model to determine the production and consumption in free trade between nations.
/economics #global economy #from zhihu