Ben Reiniger @bmreiniger@mathstodon.xyz

Have you ever sent a fax?

[feel free to boost this to maximize response.]

Goodhart's Law: When a measure becomes a target, it ceases to be a good measure.

A quasi-polynomial algorithm for well-spaced hyperbolic TSP: https://arxiv.org/abs/2002.05414

This new preprint by Sándor Kisfaludi-Bak (accepted to SoCG) just came out and caught my attention. TSP is NP-hard for Euclidean points or close-together hyperbolic points. This paper shows that it's much easier when the points are widely spaced in the hyperbolic plane. The idea is to separate the input by a short line segment that the solution crosses few times and apply dynamic programming.

tfw you think you have a good, original, unseen idea and then get mini heart attacks everytime you see something that guards any remote resemblance with it

love it when i’m cooking, hit a rare ingredient, have to stop & poll my friends for substitutes

"help! wtf is red star anise?"

"my mom has some but she refuses to discuss it or acknowledge its presence in any way"
"it shows up in your spice drawer when you're ready. i guess you're not ready yet"
"you can use black star anise & Red #-2… yes, _minus_ two"
"you can’t buy it, it has to be wrenched from the grasp of a mortal foe"
"a metaphor, like the elusive blue rose"
"i saw it in a dream once"

What can you visualize in your mind at will?

I'm starting to think that instead of describing myself as a retro gamer, I should call myself a classically-trained gamer.

Did Newton invent convex hulls? I haven't received any useful answers yet from my post to the HSM stackexchange (https://hsm.stackexchange.com/q/11401/11029) but maybe someone beyond that site knows something relevant.

ah yes, the classic proof

rock-paper-scissors but with quaternions

Consider the algorithm "M(x): if x<0 return -x, else return M(x-M(x-1))/2". This algorithm terminates for all real x, though this is not so easy to prove. In fact, Peano Arithmetic cannot prove the statement "M(x) terminates for all natural x". Paper to come! Joint work with @jeffgerickson and @alreadydone

Ringel’s conjecture solved (for sufficiently large \(n\)): https://gilkalai.wordpress.com/2020/01/27/ringel-conjecture-solved-congratulations-to-richard-montgomery-alexey-pokrovskiy-and-benny-sudakov/

This goes back to 1963 and states that the edges of the complete graph \(K_{2n+1}\) can be partitioned into \(2n+1\) copies of your favorite \(n\)-edge tree. The new preprint claiming a proof for large-enough \(n\) is https://arxiv.org/abs/2001.02665

Tree

Is anyone planning anything for the next palindrome day, 2020-02-02?

Nonbinary folx don't get why people think Pluto was demoted.

Pluto is happy no one's making it do planet shit anymore. You don't clear your orbit, and we're finally respecting that instead of demanding you act like your siblings.

Also it's the type specimen of its own category now, which I always thought was a really cool thing to be.

In hindsight, this should have been a sign, but 10-year-old me didn't have that context.

Extremely number theorist take...

Oh wow, this only happens finitely often, that's like almost never, sweet!

#NumberFields #NumberTheory Does anyone have good references other than Milne for CM fields? I'm up to my ears in them and a few basic properties in a citation-friendy format would go a long way.

It's really frustrating when I should be able to re-derive what I need, but get muddled along the way every time. This should be already done stuff.

Has anyone figured out yet whether Snaky is a winner or loser in generalized ticktacktoe? It looks like the question is still open, but if anyone has any definitive sources...

"I wish we would have the year of the linux desktop" the monkey paw curls and we see students leaving school, having only used ChromeOS for schoolwork and browsing; they come to start buying them to use at home because its whats comfortable to them. Yet another closed ecosystem is forced upon us, this time built on top of the Linux kernel instead of NT or XNU.

Robert MacKay's Chaos Machine. Its configuration space is a genus three surface. The dynamics of the machine are equivalent to geodesic flow on the surface, which is Anosov, hence chaotic.