I also got one for catching DEK out for claiming "Alan Turing broke the Enigma".
That claim goes to the Polish cryptoanalyst Marian Rejewski instead, of course (https://en.wikipedia.org/wiki/Marian_Rejewski); what Alan Turing and Tommy Flowers did was automate the breaking, which was important because it had to be done again every day (due to the many combinations of configurations of the Enigma).
The error was saying that "infinitely many alphabets can be generated" but there is a finite number of parameters which have a finite range of values. If Knuth has just written "a humongous number of alphabets" he would be correct.
Sure. For practical purposes, the number is infinite. This is why I found the bug and the bug report so amusing: In "normal" language, the sentence is correct, but for a mathematician, especially such a renowned professor, it is an amazing blunder. Bonus points for being the first word in the document.
> "These account balances reflect only the rewards for errors reported since the beginning of 2006. Many reward checks were issued during 1968--2005, too numerous to mention here."
There's 20 years on that chart vs 37 not on it.
Also that's "account balance" rather than "the most Reward checks" which I take to mean "the most [number of] reward checks" -- there's probably a correlation, yes, but [0] shows a variety of ways where check values are non-constant.
Udo's knowledge of TeX is absolutely stunning, so I would be very surprised if he weren't in first place. And DRF [0] [1] seemed to agree with the ranking in a sibling comment [2], which is also suggests that it's accurate.
> There's 20 years on that chart vs 37 not on it.
The reward values have increased exponentially over the years (I think?), so the older years should be relatively insignificant to the overall balances.
Well, I'm #4, but it's all from TeX stuff (where I'm kind of a ringer), and not The Art Of Computer Programming. The beyond-amazing Udo Wermuth is also all TeX, I believe, and did it without having a home team advantage; everyone else high on the list looks to be strictly TAOCP.
that's not what I was asking, I was asking Mr. Fuchs his pronunciation of the color named after the fuchsia flower named after the biologist Dr. Fuchs.
He is quite methodical and meticulous --- I doubt that there is much in the training data which isn't already accounted for in his research for his writings.
I only managed to get one check (for an error and a point of improvement) for _very_ minor points in _Digital Typography_ which was facilitated by my having been fascinated by typography since reading Oscar Ogg's _The 26 Letters_ and his cousin Warren Chappell's _The Living Alphabet_ when I was 8 or so.
They definitely have; lots of the recent bug reports [0] explicitly acknowledge AI assistance. You can also look at the list of pending bug reports [1] and see how many are from 2026 compared to other years (and it takes many months to get the bug reports enough to add them to this list, so this significantly undercounts things).
It kills me that I was rebuffed when I asked for copyright permission to reprint the Tolkien text _The Old English Exodus_ on the grounds that I was a "Tolkien Nut" and not an academic, then, then I bought a boxed set (which contained 4 other books which I already owned), reading the book revealed 20 typos in the 22 pages comprised of the Select Bibliography and poem (they really should've just used a scan of those twain as was done in other similar texts).
Similarly, it's hard to take current discussion of _Dune_ seriously when the word "pogrom" is set as "program" in the e-book (and yes, I have reported this as a typo, and no, it hasn't been fixed, even though the publisher did "update" the book to change the cover).
I have also found that there are a lot more errors in books published post 1990, then pre. Specifically, in the 1940-1988 period, and more specifically, in the decade from 70 to 80, the quality of books was at its acme. Errors were far less than what we see now.
Tolkien was a memorable read. I read it when I was experiencing Covid-caused depression in 2021.
and as implied in that link, have been reading his work since I was quite young, and dipped into the scholarship and linguistic angle when I picked up the paperback edition of _A Tolkien Compass_ in the early 80s.
I am now on a Trollope binge. That man distilled all of his hard life experiences as musings interspersed between the social dilemmas his characters were facing.
Recommend you start with either the "Eustace Diamonds" or "The small house at Allington".
_Tolkien's Modern Reading_ has the following on Trollope which seems pertinent:
"His (JRRT's) appreciation of (realistic fiction) is underscored by his knowledge of that keen-eyed observer of contemporaneous political and ecclesiastical culture, Anthony Trollope."
I am currently trying to patch up my rather spotty education by listening to books on Librivox, trying for chronological order, so as to build a solid foundation and understanding thereby.
I went on a big-time Trollope binge around 1990. The mis-hyphenation of “wertherian”¹ in the Penguin classics edition of one of his books led to my first contribution to the TeX hyphenation exception list.
⸻
1. The OED gives him first prose² usage credit for the word which later appeared in Russian in Tolstoy’s Anna Karenina which, I discussed over email with the translator of the edition I read and he said that Tolstoy was a big Trollope fan and likely picked up the word from him.
2. The first recorded usage was in a poem, whose name and author I forget and I’m too lazy to bother going through the steps to access the OED online via the Chicago Public Library to look it up now.
(Correction: Wertherian is in Barchester Towers which I read in a Signet Classics paperback. Most of the later books from the Barsetshire novels I read in Penguin Classics, although some I bought in cheap Oxford hardcovers.)
Wow, I didn't know Wertherian was an adjective! To be sure, Trollope himself or someone he knew may have experienced these feelings which show themselves in many different archetypes and due to different causes: in Mr. Gibson, in John Eames, in Adolphus Crosbie, etc. Sometimes it also appears in women characters.
There’s a biography of Graham Greene published in the 90s which had a gross editing error where a section was copy-pasted from one part of a chapter to another but the original was left in place.
I’m reading a novel at the moment which aggravated me when in the first chapter the narrator talked about knowing when another character had after-school activities and then two pages later talked about how that character had no after-school activities. It made me much less forgiving about “AP Geometry” and “dual” for “duel.” Overall, the book is ok, but not great.
Bjarne Stroustrup did, at some point at least. I have a $32 real check from him for finding an error in "The C++ Programming Language (Special Edition)".
It was a bit more than 25 years ago for me, check #790 for $2.88 DT 33, (143).
Really need to find another error or point of improvement so as to get the digital account --- I've been reading through TAoCP Vol. 4 Fascicle 7 on _Constraint Satisfaction_, but it's been slow going (though I did find out that it is intentional that he not list beginning of chapter quotes in the index).
Sadly I think this is the end of an era. Someone should probably run an AI fact checker on this and send him the rest of any errors. Or he could change the nature or requirement of the reward, if somehow it can be proved the error could not have been found without a human's effort.
True AGI will arrive when an LLM will be able to provide ALL remaining mistakes in Donald Knuth's books. And kill one more amazing thing in the process.
Just FYI for HN - if there is anyone looking to make big money in the coming years there are no fully signed TAOCP first editions anywhere. You would honestly print so much money if you could get all the first edition volumes signed.
He is incredibly generous with his signings --- even doing one on the spur of the moment in his home when one of the presenters mentioned that he'd been unable to source a copy of _Mathematical Fun and Games_ (I had a copy I'd planned on getting signed, but instead passed it to his wife and insisted that she get a photo of DEK signing it for her husband and that they keep it).
I wondered how you received a real check since Knuth has not been sending out real checks (as you have noted) for some time now, only to see that you explained it in the very first sentence and I had read over it, just like many people read over the error that you found in the first sentence of the book. Nice one!
When I was making my presentation at TUG 2019 he suggested _dart_ as a term for a shape of "two straight edges, one concave arc" which then freed up _arrowhead_ for "two convex, one concave arc".
I wonder if someone has used an LLM yet to analyze Knuth’s books and find errors to inundate him with? Please don’t do that (although I’m sure it’s possible).
Heh, and I thought I was being pedantic with my reward cheque. In my case I found inconsistent hyphenation in a technical term used in the book. I had wondered how to hyphenate it in my own writing so turned to Knuth to see what he did and was surprised to find it inconsistent even within a single volume of TAOCP! He wrote back with a funny message and a cheque for the back of San Serrif. It's on my wall now.
81 comments
[ 1.5 ms ] story [ 9.4 ms ] thread(Hmm maybe I should also write a blogpost about this)
That claim goes to the Polish cryptoanalyst Marian Rejewski instead, of course (https://en.wikipedia.org/wiki/Marian_Rejewski); what Alan Turing and Tommy Flowers did was automate the breaking, which was important because it had to be done again every day (due to the many combinations of configurations of the Enigma).
https://en.wikipedia.org/wiki/Bombe cites Turing, Welchman and Rejewski.
I would say he could have even gotten away with “functionally infinite number of alphabets”.
For a view into problematic shame: https://www.amazon.com/dp/159285849X
https://www-cs-faculty.stanford.edu/~knuth/boss.html
My guess for the top slot off the top of my head was actually #4.
> "These account balances reflect only the rewards for errors reported since the beginning of 2006. Many reward checks were issued during 1968--2005, too numerous to mention here."
There's 20 years on that chart vs 37 not on it.
Also that's "account balance" rather than "the most Reward checks" which I take to mean "the most [number of] reward checks" -- there's probably a correlation, yes, but [0] shows a variety of ways where check values are non-constant.
[0] https://en.wikipedia.org/wiki/Knuth_reward_check#Reward_amou...
Udo's knowledge of TeX is absolutely stunning, so I would be very surprised if he weren't in first place. And DRF [0] [1] seemed to agree with the ranking in a sibling comment [2], which is also suggests that it's accurate.
> There's 20 years on that chart vs 37 not on it.
The reward values have increased exponentially over the years (I think?), so the older years should be relatively insignificant to the overall balances.
[0]: https://www.overleaf.com/blog/618-an-interview-with-david-fu...
[1]: https://tug.org/interviews/fuchs.html
[2]: https://news.ycombinator.com/item?id=50037551
The fuchsia flower (the color comes from it) is named after a biologist named Fuchs.
I personally call the color Fuchs-ia as it should be.
my question of him was more interesting than your answer to me
I only managed to get one check (for an error and a point of improvement) for _very_ minor points in _Digital Typography_ which was facilitated by my having been fascinated by typography since reading Oscar Ogg's _The 26 Letters_ and his cousin Warren Chappell's _The Living Alphabet_ when I was 8 or so.
[0]: https://tug.org/pipermail/tex-k/
[1]: https://tug.org/texmfbug/newbug.html
SFAIK, only Findlay/Watt duo have offered such a guarantee of correctness.
It kills me that I was rebuffed when I asked for copyright permission to reprint the Tolkien text _The Old English Exodus_ on the grounds that I was a "Tolkien Nut" and not an academic, then, then I bought a boxed set (which contained 4 other books which I already owned), reading the book revealed 20 typos in the 22 pages comprised of the Select Bibliography and poem (they really should've just used a scan of those twain as was done in other similar texts).
Similarly, it's hard to take current discussion of _Dune_ seriously when the word "pogrom" is set as "program" in the e-book (and yes, I have reported this as a typo, and no, it hasn't been fixed, even though the publisher did "update" the book to change the cover).
Tolkien was a memorable read. I read it when I was experiencing Covid-caused depression in 2021.
It's interesting how different folks approach his oeuvre --- I have a fairly extensive collection:
https://www.reddit.com/r/tolkienbooks/comments/1oa01zr/four_...
and as implied in that link, have been reading his work since I was quite young, and dipped into the scholarship and linguistic angle when I picked up the paperback edition of _A Tolkien Compass_ in the early 80s.
I am now on a Trollope binge. That man distilled all of his hard life experiences as musings interspersed between the social dilemmas his characters were facing.
Recommend you start with either the "Eustace Diamonds" or "The small house at Allington".
_Tolkien's Modern Reading_ has the following on Trollope which seems pertinent:
"His (JRRT's) appreciation of (realistic fiction) is underscored by his knowledge of that keen-eyed observer of contemporaneous political and ecclesiastical culture, Anthony Trollope."
I am currently trying to patch up my rather spotty education by listening to books on Librivox, trying for chronological order, so as to build a solid foundation and understanding thereby.
⸻
1. The OED gives him first prose² usage credit for the word which later appeared in Russian in Tolstoy’s Anna Karenina which, I discussed over email with the translator of the edition I read and he said that Tolstoy was a big Trollope fan and likely picked up the word from him.
2. The first recorded usage was in a poem, whose name and author I forget and I’m too lazy to bother going through the steps to access the OED online via the Chicago Public Library to look it up now.
By the by, for a Russian writer of Trollope caliber, I recommend M. Lermontov.
Wow, I didn't know Wertherian was an adjective! To be sure, Trollope himself or someone he knew may have experienced these feelings which show themselves in many different archetypes and due to different causes: in Mr. Gibson, in John Eames, in Adolphus Crosbie, etc. Sometimes it also appears in women characters.
I’m reading a novel at the moment which aggravated me when in the first chapter the narrator talked about knowing when another character had after-school activities and then two pages later talked about how that character had no after-school activities. It made me much less forgiving about “AP Geometry” and “dual” for “duel.” Overall, the book is ok, but not great.
Really need to find another error or point of improvement so as to get the digital account --- I've been reading through TAoCP Vol. 4 Fascicle 7 on _Constraint Satisfaction_, but it's been slow going (though I did find out that it is intentional that he not list beginning of chapter quotes in the index).
thank god it wasn't that lol
One can infer that the post's URI is like a "directory" of the subresources for the post, including those images; the URL of
(n.b. the trailing slash) adjusts the resolution of the image's relative-ref now to: And the images load. Yes, trailing slashes in URLs are significant in the case of resolving a relative ref like that.If the author is here, you might consider redirecting the non-slash to the slash.
> But why will you find me there with the entry “0x$1.20”, i.e. decimal $2.88?
I know Knuth has his own notation here, (it is clearly noted at the bottom of the BOSS page) but 0x1.20 should really be decimal 1.125.
The Tex policy is that all bugs are to be fixed while Donald Knuth lives, after which the version becomes π and "all bugs are declared features".
Imagine if all the bugs just got fixed instead, and it was due to artificial intelligence! No, I don't think he'd mind at all. https://www-cs-faculty.stanford.edu/~knuth/papers/claude-cyc...
I had received a check recently and wrote about it too https://news.ycombinator.com/item?id=49286258
[0]: https://tug.org/TUGboat/tb43-3/tb135chernoff-lwc.pdf
You missed out on a great time at TUG26 [0], but hopefully I'll see you at TUG27 [1] in Paris :).
[0]: https://tug.org/tug2026/
[1]: https://tug.org/tug2027/
TUG28 will maybe be in Toronto (but this not official yet and could still easily change), which is pretty close to the US east coast.
note "now" is April 2026