main: Page 1 of 2

  • Fun with Mobius strips

    So here at Westminster we do a “Spooky Science” community activity thing each year around Halloween. I've run the following activity about spoooooooky non-orientable surfaces a couple of times, and people of many ages (from 6 to 66!) have fun with it. Also fun in classrooms!

  • An old thread from Twitter about "cheating"

    Friend of mine just asked me for an old twitter thread I wrote one time about how I turned a “cheating” moment into a learning moment. I had to dig it out of the json files in my twitter archive (relatedly, if anybody knows a good way to pull a thread out of the twitter archive, rather than just individual tweets or replies, hit me the fuck up), so I thought I would post it here on The Blog for accessibility slash future reference.

  • The Peter Q. Keep Memorial Award for Excellence in Lesson Planning

    It is probably important to note two things at the outset: (a) I do not have direct knowledge as to whether Peter Keep's middle initial is indeed Q (but it's the funniest letter), and (b) Peter Keep is not dead.

  • The things in these proofs are really weird

    This post is part of a three-post set (1 2 3) about groups of order $pqr$, where $p<q<r$ are prime.
    In this post, I'm reflecting on Ben Blum-Smith's classic the things in proofs are weird. I encountered such a proof while thinking about $pqr$-groups, and an even weirder one earlier in the semester.

  • Up and down the subgroup lattice

    This post is part of a three-post set (1 2 3) about groups of order $pqr$, where $p<q<r$ are prime. While thinking about such $pqr$-groups, I've collected a bunch of theorems and lemmas into a little mental toolbox. An interesting commonality between a lot of these tools is that they tell us about the relationship between various different animals in the subgroup lattice; an interesting difference is that some of them go “upwards,” some of them go “downwards,”1 and some of them even go “sideways.”

    1. If you have an opinion about “downward” vs. “downwards,” that is very nice but I don't actually care. <3 

  • $pqr$-groups

    This post is part of a three-post set (1 2 3) about groups of order $pqr$, where $p<q<r$ are prime. While designing final exam questions for my group theory class, I was playing around with groups of order 42, for no particular reason, and then a friend noticed something interesting that I wanted to try to prove more generally. Here's a complete writeup of this proof. Is it the most beautiful and elegant proof? Certainly not; you can directly quote some results about groups of square-free order being supersolvable, but I think this approach is pedagogically useful.

  • LLM policy

    At the end of the term here, I'm making a few edits / updates to my syllabus policy on the use of LLMs etc., and I decided to post it in some place that's easily shareable.

  • Weird Pep Talk

    (I needed to give this weird pep talk to a class of people learning to write proofs. I was originally going to write it as a Canvas announcement but then decided it'd be nice to be able to reference it elsewhere more easily.)

  • A card activity in Calculus 2

    Yesterday I was scheduled to teach my Calculus 2 class about the Second FTC at 10am, so of course I had a great idea for an activity at approximately 9:48am.

  • Asides in the margin in PreTeXt pdfs

    Asides are a neat feature in PreTeXt books – in the web version, they show up as cute li'l notes floating semi-transparently in the margin. However, in LaTeX builds, asides get dumped into plain text with no particular styling. This is sad so I decided to fix it.