
Donald Knuth's Christmas Lecture: A Conjecture That Had To Be True [video] - taeric
http://scpd.stanford.edu/free-stuff/live-webinars-lectures/donald-knuths-annual-christmas-lecture
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svat
(Reposting comment from
[https://news.ycombinator.com/item?id=15882184](https://news.ycombinator.com/item?id=15882184)
lightly edited.)

I attended this on Thursday. Knuth started with a problem about rectangles
inside rectangles ([https://imgur.com/faWRt2q](https://imgur.com/faWRt2q) —
it's going to be an exercise in 7.2.2.1 of TAOCP when that's published,
currently in the draft version of Pre-Fascicle 5C). He worked through some
small cases, made a conjecture, showed a problem submitted to the Monthly, and
lots of cool stuff with generating functions. The lecture was also peppered
with jokes and cool stories, including a fascinating conjecture by Bill
Gosper, who has a long history of coming up with these Ramanujan-like
identities. He also showed a wonderful conjecture (involving queens on an
infinite chessboard) that he thinks may never be proved, and showed a snippet
of his CWEB program for the problem.

Knuth is turning 80 in about a month, and his talks seem to get better every
year. (Though last year's lecture
([https://www.youtube.com/watch?v=DjZB9HvddQk](https://www.youtube.com/watch?v=DjZB9HvddQk))
on Hamiltonian Paths in Antiquity, which among other things covers Sanskrit
poems that satisfy a “knight's tour” constraint, holds a special place in my
heart — been planning to elaborate on it.)

~~~
markwhiting
Me too!

Another important thing to mention is that Knuth has a great sense of humor.

~~~
cup-of-tea
Indeed. I recently got my own copy of "The TeXbook" after having had it on
long loan from my university library many years. It's simply a joy to read and
surely one of the best software manuals ever published.

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copperx
This talk excited me as if I had learned a new programming paradigm. Sometimes
I come up with little problems in the shower, not unlike this one, but then
when I sit down with pen and paper, after working with a few examples, I hear
a little voice saying like "what's the point on working on this? I'm no
mathematician, and this is probably just a footnote on some 1000-year-old
mathematics textbook anyway."

To see Knuth work methodically through this seemingly trivial problem and get
something out of it was enlightening.

~~~
svat
Indeed! He mentions something related at 5:00 in the video
([https://youtu.be/BxQw4CdxLr8?t=300](https://youtu.be/BxQw4CdxLr8?t=300)):

> You know, people think that mathematicians have been working for hundreds of
> years and now there's tens of thousands or hundreds of thousands of
> mathematicians all spending every day working on problems so how could you
> possibly still find a simple down-to-earth problem that hasn't already been
> studied, you know, way too much? And the answer is: those problems aren't
> rare at all, they keep coming up several times a year, and this is an
> example where even this very basic problem of rectangle into rectangles has
> all kinds of, sort of, stones not yet turned.

And the other thing you mentioned is one of the reasons it's always a pleasure
for me to see Knuth's talks or read his work — he is one of the mathematicians
(like Euler and unlike Gauss) who make it seem simple: we get the impression
that we could do it too, if we spent enough time on it, that things are within
reach for us, just barely. This is so inspiring. And then of course when you
step back and look at his body of work, it's staggering! (Something like this
talk may account for about half a page of Knuth's published output, and he has
thousands of them…) That's additionally inspiring.

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knieveltech
For those of us that struggle with his cadence of speech, are transcripts
available online?

~~~
grendelt
Yes. It's difficult to listen to live. I'm (we're?) not knocking Knuth - he's
brilliant; he's just hard to follow. Once he gets going, he gets tripped up
with all that's going on in his head and the "uh uh um" throws off the flow.

~~~
c3534l
I think that's just how old people talk sometimes.

~~~
nocman
It's got nothing to do with his age, as far as I can tell Don Knuth has always
spoken this way (though I suspect it may have gotten more pronounced [ no pun
intended ] as he has gotten older).

I agree with what others have said. I think he just has 50 things going
through his mind at any one moment, and the part of his brain that is
controlling his speech just isn't always sure which of those 50 things it
should be sharing at that moment.

I think any of us would be fortunate to be half as brilliant as he is. And the
best part is, it is so obvious that he is one of the most humble and likeable
people on the planet. Always generous, patient, and never arrogant. I
personally would travel a great distance just to have lunch with the man, if
ever given the opportunity.

A prime example in this video is the person who keeps interrupting him to tell
him he had missed a line in his diagram. To be honest, my first reaction
(after the guy had repeated it for like the 4th time or something) I was a
little perturbed, and wished the guy would just shut up and let Don continue.
But what was Don's reaction? After he finally understood what the guy was
saying, he saw the error, corrected his mistake, and _thanked_ the guy for
"saving him 20 minutes".

Thank you Don Knuth! Not only are you brilliant, humble, hard-working and
kind, you are a gentleman's gentleman, and the the world needs more men like
you!

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mabbo
Is the K in his name actually not silent? Huh. I've been calling him "Nooth"
for ages. That's going to be hard to unlearn.

~~~
tjr
[http://www-cs-faculty.stanford.edu/~knuth/faq.html](http://www-cs-
faculty.stanford.edu/~knuth/faq.html)

 _How do you pronounce your last name?

Ka-NOOTH._

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username223
Thank $DEITY for "youtube-dl". It's a bummer that Stanford can't afford to
host its own videos, though.

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geoka9
This is tangential to the topic, but of you use TeX or any related system
(latex, texinfo, cweb, metapost, etc.), please consider becoming a TUG (TeX
User Group) member. They rely on membership and donations to keep going (and
there are some tangible benefits to being a member, too).

[https://tug.org/join.html](https://tug.org/join.html)

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shaunxcode
Anyone here know how I can get ahold of knuth without email? Hit my email in
profile. I would like to help him finish his proof.

~~~
svat
\- See
[https://cs.stanford.edu/~knuth/email.html](https://cs.stanford.edu/~knuth/email.html)
— just send a letter to his Stanford address.

\- You may have misinterpreted the talk. There's already a proof (even for the
closed form of the leading coefficient), by someone (I have the name written
down somewhere but it's in the video). You might enjoy submitting a solution
to the AMM problem instead (which only asks for the rate of growth, but if you
have a fuller proof I'm sure that's good).

~~~
jhncls
In the video Donald refers to Walter Stromquist.

