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

The rainy season is already over here, almost one month earlier than usual. The summer is going to be long in Japan.

[A] good science-fiction story is a story about human beings, with a human problem, and a human solution, that would not have happened at all without its science content. — Theodore Sturgeon

The battle system is the same since SMT3, each party member gets a turn, and gets one more for hitting an effective move; while the same holds for you enemies. My build choice was a mix of physical attack, with some support moves; I got my demons to have magics and other support skills. I still need to play the New Game+ to get the ending I actually wanted.

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The demons are based on creatures/gods of many real world religions. While they include many from christian mythology, most are from other religions (the shinto god which names the shrine near my home was in SMT4). The main character can befriend and fuse them. You actually need to convince/bribe demons to have new partners, so it’s not just a random throw, and each one has a different approach. Also the main character has a nice hair.

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Shin Megami Tensei V (2021)

I decided to buy my switch when this was announced a few years ago. It fulfilled my quite high expectations. It’s a quite solid dungeon crawler with an okay story. While it’s story is a little bit sparse, it’s main beats hit hard. One could say it is a more modern take on SMT3. You travel through a post-apocalyptic Tokyo, can befriend demons (maybe a not good choice for the english translation), and things happen.

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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/\(\infty\).

My last week’s presentation is on YouTube:

I talked about the connection between determinacy for infinite games and reflection principles, in reverse mathematics. (All are things I want to talk about here, later.)

My paper was accepted at WoLLIC! Now I need to polish it up (and make preparations for the trip)!

So, I spent a week at Paris (and two days sleeping after getting back home). Pretty nice to go to a maths event after such a long time, and also had the chance to give a talk. Though it still feels pretty weird to go to places where people are not masked...

if it exists, it will be misunderstood on hackernews

Tomorrow is my time going out of Japan since 2019. I’m a little bit anxious, but I’m gonna do a talk on next Wednesday so I’m happy.
(Slides are also finished, until I find mistypes)

Today I have a summer research student starting and I'm going to have to let her in on the (somewhat embarrassing) secret that Fortran is still one of the fastest languages out there for what we need to do, then have her install a fortran compiler. Welcome to the future, student!

More on this game can be found in van Benthem’s “An essay on sabotage and obstruction” and Aucher et al. “Modal logics of sabotage revisited”. There is quite a lot more about these sabotage games and its related sabotage logic in the literature. This logic allows us to erase edges from a graph, and gives a formalization of the sabotage game. (I’ve been reading about them this week, trying to find something amenable to work on.)

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Answer (long) 

Blocker first cuts one edge connecting the center to the bottom right. He then erases the nodes connecting Runner’s current position and the exit node (if there is no such edge, he may erase any edge).

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The sabotage game has two players: Blocker and Runner, Every turn, Blocker erases one edge and then Runner moves one step. Runner wins the game iff they can reach the ‘exit’ of the graph.

In the graph below, who wins the game?
Answer below.

For clearness: the start is at the upper left corner, and the exit is at the lower right corner. The graph is non directed multigraph, so there are two paths from the start to the center and so on.

This puzzle is originally by van Benthem,

Since I’m already talking about my experience here, I think I should thank @christianp and @ColinTheMathmo for administering Mathstodon. This server in general felt quite welcoming, and I was a little scared about the feediverse. In addition, their posts are pretty interesting!

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I think a month and something passed since I created an account here. I’m using the birdsite less (and planning to semi-retire my account there). There are still some people that I like hearing about there, so I’ll probably just mute things proactively.

I think the biggest differences for me is that here everything feels a little more slow and there is a lot less screaming to the void. In general it feels a little better here.

Learning pure mathematics is a bit like being bewitched and turned into a bird. It's an amazing experience. But when you try to tell everyone about it, they don't understand a word you're saying. Most of them walk right by.

Btw, I’m playing on the PS3, so it’s a 11 year old game that has a 4 years old remake.

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