Leonardo Pacheco @leonardopacheco@mathstodon.xyz

#introduction
I study logic at Tohoku University.
Currently focused on reverse mathematics and modal logic, mostly using games.

I’ll use this thread to register a few comments on games I’ve been playing recently. Most of them will be JRPGs, but I’ll also post about other genres. These will be mostly spoiler freeI will probably add one or two reviews whenever I’m in the mood.

So 0/\(\infty\).

Does anyone know of a some text explaining the difference between intension and extension? Especially a reference for people who are not used to this terms in logic or philosophy.
Trying to think a simple explanation by myself, but with little success.

#math #philosophy

still cute

cute sleepy hamster

Two bad deontic axioms:
- The principle of fait accompli: If we do something we ought not to do, we ought to do it.
- The principle of continuous moral rectitude: If something ought to be, whatever is the case ought to be.

(Names given by Prior. These axioms hold in older proposals for deontic logic by Mally and Gelling. Paraphrased from Føllesdal and Hilpinen’s paper “Deontic logic: and introduction”.)

I’m beginning to have confidence in my writing. It’s still not good, but I can finally sit and put things in the paper (and then come back and edit). There is some chance that writing my PhD thesis will probably be less painful than when I wrote my masters thesis.

I don’t get why so few streaming sites here in Japan have subtitles. The only ones that are usually available are japanese subtitles for foreign movies (the exceptions are mostly Netflix produced things).

Finally discovered the classification system of my university’s library: the National Diet Library Classification. I couldn’t find any good reference in English though. There’s only this mostly Japanese with annotations in English (but not always): https://www.ndl.go.jp/jp/data/catstandards/classification_subject/ndlc.html
At least they put maths at MA, other things have no relation.

University asked me to get my guardian’s permission to go to a trip, that is, to email my mom on the other side of the globe and ask if it’s okay to go present a paper in a conference in another country.

That’s because I’m a PhD _student_. The other realistic option I’d have for a guardian would be my wife. This policy makes no sense🤷

I don’t know why, but my hamster started shooting poop from her mouth last month. She climbs on my hand and after a few moments just shoots it. 🤷

Craig Smoryński on the proof of the existence of fixed-points for GL (or the de Jongh—Sambin Theorem):

“De Jongh’s original proof was semantic and so complicated he never showed it to anyone; Sambin’s original proof was syntactic and so complicated I never read it completely.”

Speaking of Undertale, it is probably the most emotional games I’ve ever played. If you like story games (with a few action(?)/RPG elements, just play it. Better enjoyed spoiler-free.

3-end

Started playing Moon this week on my Switch. Pretty quirky game, the writing and character design is just great. Unfortunately it is a little too slow for my head to handle. A few qualities of life would have made it perfect (at least fast-forwarding would be pretty useful for experimenting). It is quite an experience, if you are in the right mindset. It also inspired undertale.

2-end

Had fun filling another (japanese) form today.
- Hard limit on name length: mine is longer than permitted, had to use only one surname in place of my “full name”.
- Sees difference between full-width and half-width numbers: because of course ３ and 3 are different characters.
- Requires me to retype the password manually: of course my password manager is not to be trusted.
- Bonus: doesn’t indicate where the wrong input is, so trial-and-error is required.

Trying to use Zotero, as my manual bookkeeping was becoming too much work.