5 ms·
Related tweet from Russ Cox: https://twitter.com/_rsc/status/1483899960684863493 https://twitter.com/_rsc/status/1483899960684863493 > Knuth is making backward
by svat 4y ago
Related tweet from Russ Cox: https://twitter.com/_rsc/status/1483899960684863493 https://twitter.com/_rsc/status/1483899960684863493
> Knuth is making backwards incompatible changes to fix bugs in something he wrote 54 years ago (TAOCP volume 1, 1968)!
And mine:
Apart from the care Knuth takes, what's remarkable is that he has basically put out a permanent invitation to a DDoS on his time and attention—everyone in the world is invited to contact him about every word he has ever written—and somehow still continues to produce new material.
From Wilf's toast/roast of Knuth (https://www2.math.upenn.edu/~wilf/website/dek.pdf https://www2.math.upenn.edu/~wilf/website/dek.pdf):
“[…]your letter will be placed on a stack that already has 5,379 letters that reached him before yours did,[…] while he completes his latest additions to 47 new manuscripts and 311 revisions of already existing books.”
- tambourine_man 4y agoI think the secret is he uses letters. Try that invitation to a DDoS on his life with Twitter or email. If you’re willing to post a physical letter, chances of the content being worth reading are a lot higher.
- ReactiveJelly 4y agoIt's hashcash! But the hash is literal cash of about 50 cents
- femto 4y agoWith a further optimisation in the batch handling of snail mail: "I have a wonderful secretary who looks at the incoming postal mail and separates out anything that she knows I've been looking forward to seeing urgently. Everything else goes into a buffer storage area, which I empty periodically." from: https://www-cs-faculty.stanford.edu/~knuth/email.html https://www-cs-faculty.stanford.edu/~knuth/email.html
- svat 4y agoJust to clarify, you can email him to report errors in any of his books (and I have done so, several times). It's only for other general communication that he insists you use physical email.
- krisrm 4y agoThat is a fantastic and highly amusing speech, thank you for linking it.
- svat 4y agoYou may also like this other speech by the same author (Herb Wilf) that I love too (on an unrelated topic): • Epsilon Sandwiches https://www2.math.upenn.edu/~wilf/website/MAASpeech https://www2.math.upenn.edu/~wilf/website/MAASpeech In fact everything by Wilf that I've read is lovely: the paper "Recounting the rationals" (https://www2.math.upenn.edu/~wilf/website/recounting.pdf https://www2.math.upenn.edu/~wilf/website/recounting.pdf with Neil Calkin), and the book generatingfunctionology https://www2.math.upenn.edu/~wilf/DownldGF.html https://www2.math.upenn.edu/~wilf/DownldGF.html
- JadeNB 4y agoEpsilon sandwiches is a great speech, with advice that I wish I could follow—but it pre-supposes students for whom the referenced very easy proofs are indeed very easy conceptually, and the struggle is only to put those concepts into words. I can believe that this is true of students in a UPenn first analysis course, but it is not true at the less prestigious university where I teach students who are encountering proofs for the first time (well before analysis)—and I have long struggled with how to break down this two-step complication into separate manageable steps with students for whom, say, it is still a real challenge to understand (in the context of proving facts about sums and products of even numbers) why 2(x + y) = 2x + 2y is true, but 2(xy) = (2x)(2y) is not. If anyone knows how to adapt Wilf's advice to such students, then I—and they, in my fall class!—will be grateful to hear it!
- dento 4y agoI case it helps, this is how it was taught to me when introducing proofs. For your example case, it's simply the matter of seeing multiplication as repeated addition. So, 2x is x+x, and from this follows: 2(x+y) = (x+y)+(x+y) = x+y+x+y = x+x+y+y = 2x+2y However, for the other case, when we convert the multiplication by 2 to an addition and back: 2(xy) = (xy)+(xy) = xy+xy = 2xy Now we can show that this works for n instead of two: n(x+y) = (x+y)+..[n times]..+(x+y) = x+..[n times]..+x + y+..[n times]..+y = nx+ny And for multiplication: n(xy) = xy+..[n times]..+xy = nxy
- lou1306 4y ago> Apart from the care Knuth takes, what's remarkable is that he has basically put out a permanent invitation to a DDoS on his time and attention—everyone in the world is invited to contact him about every word he has ever written—and somehow still continues to produce new material. I mean, this is just a best practice among academics -- every paper has at least one corresponding author to whom you should write for all inquiries about it. Of course, Knuth's immense popularity and the chance you may get a reward [0] contribute to the intensity of the DDoS. [0]: https://en.wikipedia.org/wiki/Knuth_reward_check https://en.wikipedia.org/wiki/Knuth_reward_check (of course, the "reward" is not really the money, but rather getting recognition from Don Knuth himself)
- smitty1e 4y ago> everyone in the world is invited to contact him about every word he has ever written But not by email.
- lou1306 4y agoWell, as others have pointed out, at his scale this is likely a necessary rate-limiting countermeasure. Even relatively obscure academics easily end raking up hundreds of emails in their inboxes once they are senior enough. With someone as popular as Knuth, it would be madness.
- svat 4y agoYes by email (search the posted page for "@" or look under "Rewards" at https://cs.stanford.edu/~knuth/taocp.html#:~:text=Rewards https://cs.stanford.edu/~knuth/taocp.html#:~:text=Rewards ) And when I said "invited" I meant "strongly incentivized": by offering cash rewards (initially) and those highly prized "Knuth checks", he surely gets orders of magnitude more scrutiny and error reports than a typical academic.