Cazzandro @KodeGhinn@qoto.org

Applied Category Theory course by @johncarlosbaez:
https://math.ucr.edu/home/baez/act_course/index.html
Very short, self-contained lessons, great for casual reading with concrete applications!

Today at 3 pm UK time I'm giving a quick intro to n-categories. You can join us online here:

https://ed-ac-uk.zoom.us/j/82270325098
Meeting ID: 822 7032 5098
Passcode: XXXXXX36

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

With luck I'll be able to put my talk on YouTube later.

Here's what I'll explain:

An n-category is a gadget with objects, morphisms between objects, 2-morphisms between morphisms, and so on up to n-morphisms. The 'periodic table of n-categories' shows the pattern you get if you look at (n+k)-categories that are boring at the bottom k levels, with just one object, one morphism, and so on for a while. You can think of these as n-categories with k ways to multiply objects. The Stabilization Hypothesis claims that once k reaches n+2, increasing it more has no effect!

I'm giving a public talk next week:

• Life's struggle to survive. Tuesday September 26, 6 pm UK time. Room G.03 on the ground floor of the Bayes Centre, 47 Potterrow, Edinburgh.

When pondering our future amid global warming, it is worth remembering how we got here. Even after it got started, the success of life on Earth was not a foregone conclusion! In this talk I recount some thrilling, chilling episodes from the history of our planet. For example: our collision with the planet Theia, the "snowball Earth events" when most of the oceans froze over, and the asteroid impact that ended the age of dinosaurs. Some are well-documented, others only theorized, but pondering them may give us some optimism about the ability of life to survive crises.

To attend in person, get a free ticket here: https://www.eventbrite.co.uk/e/lifes-struggle-to-survive-leverhulme-lecture-tickets-707700620607

Refreshments will be served after the lecture. If you actually show up, say hi!

If you can't join us, fear not: I should be able to put a recording of the talk on my YouTube channel eventually. And you can see the slides here now:

http://math.ucr.edu/home/baez/struggle/

If you find mistakes in them or just have questions, please let me know! I'm still polishing the slides - and the more questions I field now, the more prepared I'll be when it comes time to give the actual talk.

A few weeks ago I made up a "fake prime function" to illustrate that a certain property wasn't really a property specific to primes. I notice @johndcook wrote about it a couple of times

https://www.johndcook.com/blog/2023/08/21/fake-primes/

https://mathstodon.xyz/@johndcook/110927666845223894

In the back of my mind was Cramer's "model" of the primes although I was interested in different statistical properties https://terrytao.wordpress.com/tag/cramers-random-model/

For anyone unaware, Google Chrome is currently rolling out an update that track your interests based on browsing history, then share them with 3rd party websites. The notification page makes it sound like they added a new privacy feature, but in actuality they've automatically enrolled you into their tracking system and you have to go and manually opt out.