4chan post solving anime math problem possibly solves a 25-year-old math problem - Sensationalist Headlines

https://www.theverge.com/2018/10/24/18019464/4chan-anon-anime-haruhi-math-mystery A 4chan poster may have solved part of a very tricky math problem that mathematicians have been working on for at least 25 years. The user was just trying to figure out the most efficient way to watch episodes of a nonlinear anime series, but the result has generated considerable interest from mathematicians around the world who have no way to identify the anonymous user. The 4chan part of this saga began on September 17th, 2011, when a poster posed a question: if you wanted to watch 14 episodes of the anime The Melancholy of Haruhi Suzumiya in every possible order, what’s the shortest string of episodes you’d need to watch? An anonymous poster figured out one possible way to solve to the 4chan problem, satisfying the more mathematically inclined Haruhi fans. But in the process, they also helped puzzle out an issue that mathematicians have been working on since 1993. The anonymously authored proof (which was recently reposted on a Fandom wiki) is currently the most elegant solution to part of a mathematical problem involving something called superpermutations. It’s an enigma that goes well beyond anime. With the Haruhi problem, people were looking for the shortest possible superpermutation for the 14-episode set. But no one has found a formula that would actually solve that problem. The 1993 paper suggested one part of that solution. But in 2014, Houston figured out that the math used in the 1993 problem didn’t work for sets containing more than six numbers. The result got mathematicians really excited about the problem again after it had languished in the literature for a quarter century. Eventually, one of them found the 4chan proof, and all those numbers and symbols started to fall into place. The 4chan proof outlines how to find the smallest possible number of episodes for the solution. But that doesn’t fully solve the problem. An even bigger breakthrough came earlier this month when sci-fi author and mathematician Greg Egan wrote up a proof that outlined how to find the largest possible number for any given superpermutation problem. Pantone crunched the numbers of the Haruhi problem for The Verge and found that you’d need to watch at least 93,884,313,611 episodes to watch the season in any possible order. At most, you’d need to watch 93,924,230,411 episodes to accomplish the task. There’s still a ways to go to narrow down the exact answer, but they’re getting there. Now, mathematicians have a way to figure out the range of answers, and a group of them — including Houston and Pantone — are actively working to figure out a formula that combines Egan’s work and the anonymous proof into a cohesive formula. “It might be possible to crack the thing completely open,” Houston says. Basically, mathematicians dug up an old 4chan post that solved a problem involving watching the least amount of episodes of an anime series in every possible order, use it as proof for their corresponding math problem, and found it to be plausible to find a formula for both problems. The sad part is, there's probably no way cite the person who made the original 4chan post. https://twitter.com/robinhouston/status/1054637891085918209

wym? you just cite anon, anything else would be heretical.

The power of anime.

I guess everyone in academia has already forgotten about WebCite.

So basically this is Kevin from the office, except instead of pie it's anime tiddies.

You get a hundred monkeys and give them typewriters, you get Shakespeare. Give an entire anonymous message board full of outcasts and weirdos anime, you get a 25 year old equation solved.

/sci/ is packed with STEM majors who have too much free time and a desperate need to prove that they're the mathiest. Of all the possible internet communities full of mathematicians, I'd say /sci/ is the most likely to have ended up solving a problem that stumped the scientific community.

The real question is: Do we count Endless Eight as eight episodes, or only one?

It counts as a waste of time.

Of fucking course it was about Haruhi.

I feel stupid for not understanding the posed question: What is the shortest string of episodes to watch 14 episodes in every possible order? It's always gonna be 14?

Is this the 2018 reboot of Good Will Hunting

Well if you do it all in 1 sitting, your first string will end at a particular episode number. Another string would then start on that number, so by doing the strings in a certain order you can massively reduce the amount of episodes you need to watch.

Oh. so instead of 1,2,3,4,5,6,7,8,9,10,11,12,13,14 - 14,1,2,3,4,5,6,7,8,9,10,11,12,13 it could be 1,2,3,4,5,6,7,8,9,10,11,12,13,14,1,2,3,4,5,6,7,8,9,10,11,12,13,1,...etc. so you merge the beginning of the new string with the end of the last string?

So consider a two-episode show. There's two orders you could watch them, 1-2 and 2-1. If you wanted to watch both orderings, the naive way is 1-2-2-1, but you can shorten it to 1-2-1, which still contains both orderings. (This is not a unique solution but they're all equivalent) Go up to three episodes, you get 1-2-3-1-2-1-3-2-1, which contains the six orderings 1-2-3, 2-3-1, 3-1-2, 2-1-3, 1-3-2, and 3-2-1. We've had proofs that worked for up to five, but beyond that we've just proven upper and lower bounds. This proof (AIUI) doesn't give a definite answer either but it tightened the bounds, and there's thought that maybe combining it with the previous proofs could yield an exact solution for any number.

I ninja'd you with the answer to my own question.

Counting is probably the least favorite thing I've done this semester in my probability/statistics course but it's problems like these that still spur my interest nonetheless.

I wonder if we'll ever discover the precise mathematical induction methods you need to solve this one.