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Theorem of the Day (theoremoftheday.org)
408 points by kercker on Nov 28, 2016 | hide | past | web | favorite | 30 comments

This is super interesting. I love how concisely they are able to convey a certain concept. I feel the ratio: amount of knowledge you acquire versus length of the explanation is incredibly high, which makes me want to keep opening more and more tabs. The only place where I have the same feeling is in fermatslibrary.com, although in a different way. I would like to see the same concept applied to CS.

> I would like to see the same concept applied to CS.

Definitely. An algorithm of the day would be nice.

You might find this interesting, assuming you don't already know about it:

The morning paper by Adrian Coyler


For more random interesting theorems with outrageously clever and beautiful proofs, the "Proofs from THE BOOK" [1] book is a fantastic collection. As a curiosity, "THE BOOK" in the title comes from Erdos, who often referred to the book in which God keeps nice proofs of math theorems :)

[1]: https://www.amazon.com/Proofs-BOOK-Martin-Aigner/dp/36420085...

Would be kind of fun to get this in email. Kind of like word of the day.

I second that, but my preference would be for a RSS feed.

Edit: they do have a RSS feed and other ways to get a daily theorem from their Resources page [1]

[1] [ http://www.theoremoftheday.org/Resources/Resources.htm ]

Would you look at that. That's good enough for me, thanks.

Though are you getting the full pdf's? I'm using Sage and a lot are linking to PDF's with "A newer version of this theorem description is now being hosted at: www.theoremoftheday.org/Theorems.html"

Also some are linking just to the home page. I'm wondering if this is just me or you're getting the same.

Oh dear. Yes, I'm getting the same "A newer version of this theorem..." PDFs.

My apologies. I should have checked that the RSS is returning valid links.

Well it is good enough, was just checking. Thanks.

You can use an RSS feed to email converter. I use Feed2imap (https://github.com/feed2imap/feed2imap/) to collect feeds from many sites and Notmuch (https://notmuchmail.org/) to sort and index the mess.

Am I the only one who was confused what the 'tau' referred to in http://www.theoremoftheday.org/NumberTheory/Willans/TotDWill... ?

I was also confused. Personally, I find the use of tau nonsensical -- especially when it's used alongside pi.

Established conventions should only be changed when there's a clear need to do so. Inventing a redundant constant does little other than add additional cognitive load. It's not like the tau advocates can break backwards compatibility -- there's too much literature that uses pi. The result is that everyone must now remember both pi and tau.

I think tau was used on purpose in that article to avoid confusion with the prime counting function, typically denoted pi (unrelated to the constant pi)

Yes very confused, but I think we're just overthinking it and that tau is just being used with it's normal definition.

tau = 2*pi

I wish the authors would include a small note "tau = 2*pi". Maybe one day it won't be necessary, but for the foreseeable future it would quite increase readability.

This is really interesting, but my heart hurts at the SEO value lost in having the main content be all PDFs. Not that there's really a NEED to have all of this crawl-able & indexable by search engines, but it could probably reach a whole lot more people if it was.

I disagree with the front page of this site, the "crowning achievements of mathematics" are not "her theorems", but our definitions.

“One can always find imbeciles to prove theorems.” René Thom (1923–2002)

Unrelated: when a site gets top of HN and it's made of PDF contents, I just cringe at the bandwidth usage for the next few hours...

Nah. These PDFs are look to be about 150K-300K. A typical bloated 2016 web page has an equal amount of JavaScript, let alone images, so not really worse off using PDFs.

Assuming (generously) a 100k visitors at half a megabyte per visitor, a top HN placement will only cost a few dollars in bandwidth.

Pretty cool, but the links don't work for me. I'm on Windows 10, Chrome 54.0.2840.71 64 bit.

Win10, Chrome 54.0.2840.99, works fine here. (They link to PDF files though, more likely that's the problem I suppose).

Yeah, I restarted Chrome and everything is good again. When in doubt, turn it off and back on, right? :)


Also the 2016 version for increasingly large amount of software - when in doubt, empty cache and hard reload page.

Get out of the car and get back in again.

This actually did seem to fix my partner's car for a short while just before the battery completely died. Something to do with resetting diagnostics.

Many years ago, trying to keep a NT 3.5.1 server functional, this was a frequent chant in the server room.

Perhaps you can kill a bunch of birds (especially those that hurt your privacy :)) with one stone: install Firefox ;)

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