Kudos Updated 2025-07-16
Ahh, Ciro Santilli was certain this was some slang neologism, but it is actually Greek! So funny. Introduced into English in the 19th century according to: www.merriam-webster.com/dictionary/kudo.
Hypercube Updated 2025-07-16
square, cube. 4D case known as tesseract.
Convex hull of all (Cartesian product power) D-tuples, e.g. in 3D:
( 1,  1,  1)
( 1,  1, -1)
( 1, -1,  1)
( 1, -1, -1)
(-1,  1,  1)
(-1,  1, -1)
(-1, -1,  1)
(-1, -1, -1)
From this we see that there are vertices.
Two vertices are linked iff they differ by a single number. So each vertex has D neighbors.
Hydrogen line Updated 2025-07-16
21 cm is very long and very low energy, because he energy split is very small!
Compare it e.g. with the hydrogen 1-2 spectral line which is 121.6 nm!
PostgreSQL GIST Updated 2025-07-16
The highly underdocumented built-in module, that supports SQL spatial index and a lot more.
Quite horrendous as it only seems to work on geometric types and not existing columns. But why.
And it uses custom operatores, where standard operators would have been just fine for points...
Minimal runnable example with points:
set -x
time psql -c 'drop table if exists t'
time psql -c 'create table t(p point)'
time psql -c "insert into t select (point ('(' || generate_series || ',' || generate_series || ')')) from generate_series(1, 10000000)"
time psql -c 'create index on t using gist(p)'
time psql -c "select count(*) from t where p <@ box '(1000000,1000000),(9000000,2000000)'"
The index creation unfortunately took 100s, so it will not scale to 1B points very well whic his a shame.
And if you really can't make money from a subject, there is only one other thing people crave: beauty.
There are apparently two methods:
Specific implementations:
I can't believe there isn't a YouTube video comparing various substances for each flammability and instability ratings, this would be a huge hit.
History of special relativity Updated 2025-07-16
Bibliography:
Google X Updated 2025-07-16
Wikipedia reads:
Any contributor could create and own new Knol articles, and there could be multiple articles on the same topic with each written by a different author.
so basically exactly what Ciro Santilli wants to do on OurBigBook.com. Ominous.
Like any closed source "failure", everything was deleted. wiki.archiveteam.org/index.php/Knol
Good video game to watch Updated 2025-07-16
This is a list of video games that are good to watch other people playing, even if you don't play yourself. And often they are better to watch than to play as you don't have to waste your time as much!
GitLab Updated 2025-07-16
GitLab was very important to Ciro because he wanted to base Booktree on it.
By GitHub around Black Lives Matter, due to a possible ludicrous relationship with slavery of black people:For the love of God, the word "master" is much more general than black slavery. If you are going to ban it, you might as well ban the word "evil".
Several software projects followed the purge from their codebases, maybe GitHub followed someone else's lead, it's hard to say.
The words "whitelist" and "blacklist" were also targeted.
Video codec Updated 2025-11-18
The inaugural that predicted the Josephson effect.
Published on Physics Letters, then a new journal, before they split into Physics Letters A and Physics Letters B. True Genius: The Life and Science of John Bardeen mentions that this choice was made rather than the more prestigious Physical Review Letters because they were not yet so confident about the results.
Polynomial over a ring Updated 2025-07-16
However, there is nothing in the immediate definition that prevents us from having a ring instead, i.e. a field but without the commutative property and inverse elements.
The only thing is that then we would need to differentiate between different orderings of the terms of multivariate polynomial, e.g. the following would all be potentially different terms:
while for a field they would all go into a single term:
so when considering a polynomial over a ring we end up with a lot more more possible terms.
Amazing talk by Richard Feynman that describes his experiences at Los Alamos National Laboratory while developing the first nuclear weapons.
Polymerase chain reaction Updated 2025-07-16
This is an extremely widely used technique as of 2020 and much earlier.
If allows you to amplify "any" sequence of choice (TODO length limitations) between a start and end sequences of interest which you synthesize.
If the sequence of interest is present, it gets amplified exponentially, and you end up with a bunch of DNA at the end.
You can then measure the DNA concentration based on simple light refraction methods to see if there is a lot of DNA or not in the post-processed sample.
One common problem that happens with PCR if you don't design your primers right is: en.wikipedia.org/wiki/Primer_dimer
Sometime it fails: www.reddit.com/r/molecularbiology/comments/1kouomw/when_your_pcr_fails_again_and_you_start/
Nothing humbles you faster than a bandless gel. One minute you’re a scientist, the next you’re just a pipette-wielding wizard casting spells that don’t work. Meanwhile, physicists are out there acting like gravity always behaves. Smash that upvote if your reagents have ever gaslit you.
and a comment:
PCR = Pray, Cry, Repeat

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