### Categorically Yours & Typographical Musings†

Okami's Lamy fountain pens

I

One of the marks of being a good prof is when they see that students didn’t understand something and go over it again. My algebra prof has made a habit of this, especially when he goes over stuff in class too quickly. This happened last week and left me quite furious. Someone must have mentioned something to the prof², and he went over what we saw in the last hour again. This took an hour out of the three-hour class. I appreciated. I realized that there were some undergrads in our class, who weren’t familiar with some of the more abstract concepts of category theory³. It was an issue. Class was great today. I was drinking my strong milk tea and noting stuff down. We saw direct sums and (co)universal objects. Having proofs done with commutative diagrams is so elegant and simple.

Limit of a diagram is a cone, via Wikipedia

II

I’ve got a small term paper due in December. I’ve decided to do it on the Clifford algebras of cubic forms. It’s supposed to be quite short, but I’ll pump out quite a bit of stuff so that I can nail an A.

The algebra prof told us that we’d have a take-home midterm exam. I haven’t mentioned to too many people that I have all of the solutions to all of the Hungerford problems¹.Well, most of them. I noticed today while I was printing them out that there were a few sections missing. I was definitely feeling good after he explained everything again. Not that I didn’t understand it beforehand, but it made a difference that he cared enough to go through it once more, at normal speed.

III

Canadian Multilingual Standard keyboard layout, via Wikipedia

I always use a Canadian Multilingual keyboard. For some reason, I’ve been blindly hitting a combination of keys that would give me the multiplication sign ‘×’. I was trying to figure out how this happened when I found this page on Wikipedia. I’ve kind of become interested in the Unicode characters which are available on standard keyboards. My favorites include the superscript numbers I use for footnotes, † → the dagger symbol, ‡ → the double dagger symbol, and this star symbol → ★. Other favorites include the curly brackets → { } and the abreviation for number → №. There’s the degree symbol → ° as well as the tilde → ~ and the horizontal bar → ―.

IV

I think that we’ve completed our intro into category theory. I’ll have to learn the rest by myself, as we’re delving into the structure of groups now. I’m looking forward to that, as well as Galois theory and commutative ring theory.

I really like how some proofs are just completed by commutative diagrams. It’s just so elegant. I don’t know why I find these algebraic topics so interesting. They are elegant and abstract. In analysis, we are seeing the Lebesgue measure and integral. The prof keeps saying ‘mearable’ instead of saying measurable. He also says ‘lebesgue’ by pronouncing the ‘s’, which is silent, as any French-speaker will tell you.

Another weird thing was the word integer. I was convinced that it was pronounced integer with a hard /g/, not a soft /j/. This happens because I speak three languages fluently. My wife’s favorites include catholic and patio. When I’m tired, I put the emphasis on the wrong part of the word. She finds it cute.

This is how you pronounce: ĭn’tĭ-jər.

* * * * *

[¹]: Algebra, by Thomas Hungerford, Springer Verlag, GTM Vol 73.
[²]: Not about me, but about the fact that he went too fast and that they didn’t understand. Towards the end of the class, I mentioned out loud that I didn’t get most of what he had been explaining because he was going too fast. I was basically just mumbling in my beard.
[³]: The yes girls are undergrads. I wasn’t surprised to find this out. For some reason, the prof didn’t want to get into a too high level of abstraction.

[†]: I thought this was a good play on words.
[‡]: see this footnote in this post.

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