### Young Diagrams and Classical Groups

#### Posted by John Baez

Young diagrams can be used to classify an enormous number of things. My first one or two This Week’s Finds seminars will be on Young diagrams and classical groups. Here are some lecture notes:

• Young diagrams and classical groups.

I probably won’t cover all this material in the seminar. The most important part is the stuff up to and including the classification of irreducible representations of the “classical monoid” $\mathrm{End}(\mathbb{C}^n)$. (People don’t talk about classical monoids, but they should.)

Just as a reminder: my talks will be on Thursdays at 3:00 pm UK time in Room 6206 of the James Clerk Maxwell Building at the University of Edinburgh. The first will be on September 22nd, and the last on December 1st.

If you’re actually in town, there’s a tea on the fifth floor that starts 15 minutes before my talk. If you’re not, you can attend on Zoom:

https://ed-ac-uk.zoom.us/j/82270325098

Meeting ID: 822 7032 5098

Passcode: XXXXXX36

Here the X’s stand for the name of a famous lemma in category theory.

My talks should eventually show up on my YouTube channel.

Also, you can discuss them on the Category Theory Community Server if you go here.

## Re: Young Diagrams and Classical Groups

Should that last link be this? The one you gave is to the ACT@UCR Zulip chat, not the Category Theory one.