Recent News

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Happy $1^6 3^4 5^2 7^0$

a curious progression of factors that can also be premultiplied by $(-1)^8$ and written $\prod_{k=0}^4 (2k-1)^{8-2k}$. (Others write $\bigl(\sum_{k=0}^9 k\bigr)^2$, or $\sum_{k=0}^9 k^3$.)

Some Generative AI

Oliver Manger sent me a delightful image of “dancing lynx” for my `\W-th birthday!

The first third of Volume 4C

I recently sent to my publisher (Addison–Wesley) the camera-ready copy for Volume 4, Fascicle 7 of The Art of Computer Programming, entitled “Constraint Satisfaction”. The official date scheduled for publication of this 304-page paperback is February 19. But copies can be ordered now, and you can get the best deal at informIT.com. That website also has the publisher's traditional hype about the great stuff inside.

(Or, you can see a free preview of the whole thing in compressed PostScript form: Prefascicle f7a. The contents of that prefascicle agrees fairly well with the contents of the first paperback printing of Volume 4, Fascicle 7, except for parts of the index. As usual, the prefascicle is “frozen” and will not be maintained, while the paperback will gradually improve with time.)

TAOCP update

The fourth volume of The Art of Computer Programming deals with Combinatorial Algorithms, the area of computer science where nonobvious techniques have the most dramatic effects. I love it the most, because one good idea can often make a program run a million times faster. It's a huge, fascinating subject, and Part 1 (Volume 4A, 883 pages, now in its twenty-fourth printing) was published in 2011; Part 2 (Volume 4B, 714 pages, now in its second printing) was published at the close of 2022. The first 275 or so pages of Volume 4C will be published soon, as announced above, together with an index.

While preparing many of the new exercises in Volumes 4B and 4C, I spent a lot of time attempting to improve on expositions that I found in the literature. And in several noteworthy cases, nobody has yet pointed out any errors. It would be nice to believe that I actually got the details right on my first attempt; but that seems unlikely, because I had hundreds of chances to make mistakes. So I fear that the most probable hypothesis is that nobody has been sufficiently motivated to check the finer points out carefully as yet.

I still cling to a belief that such details are extremely instructive. Thus I would like to enter here a plea for some readers to tell me explicitly, “Dear Don, I have read exercise N and its answer very carefully, and I believe that it is 100% correct,” where N is one of the following exercise numbers:

(If you're depressed by current world news, you might find some solace by immersing yourself in a bit of research into eternally beautiful patterns.)

Please don't be alarmed by the highly technical nature of these examples; more than 750 of the other exercises are completely non-scary, indeed quite elementary. But of course I do want to go into high-level details also, for the benefit of advanced readers. And those darker corners of my books are naturally the most difficult to get right. Hence this plea for help.

Remember that you don't have to work the exercise first. You're allowed to peek at the answer; in fact, you're even encouraged to do so. Please send success reports to the usual address for bug reports (taocp@cs.stanford.edu). Thanks in advance!

By the way, if you want to receive a reward check for discovering an error in TAOCP, your best strategy may well be to scrutinize the answers to the exercises that are listed above.

Preliminary sketches of material that will be in later parts of Volume 4C have also been drafted, and courageous readers who have nothing better to do might dare to take a peek at the comparatively raw copy in these “prefascicles.” One can look, for instance, at Pre-Fascicle 8a (Hamiltonian Paths and Cycles); Pre-Fascicle 9b (A Potpourri of Puzzles). Thanks to Tom Rokicki, those PostScript files are now searchable!

Oral histories

I seem to get older every day, and people keep asking me to reminisce about the glorious days of yore. If you're interested in checking out some of those videos and other archives, take a look at my news page for 2020, which I've updated with a few items captured after that year.

Public lectures in 2025

Although I must stay home most of the time and work on yet more books that I've promised to complete, I do occasionally get into speaking mode.

Sometime in December
The 29th annual Christmas Lecture

Click here for the “recent news” that was current at the end of 2024, if you're interested in old news as well as new news.

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