Are there infinitely many primes with property X by Ciro Santilli 37 Created 2024-12-13 Updated 2025-07-16
There are infinitely many conjectures asking if such types of primes also form infinite families.
Usually the answer is yes, but no one was able to prove it yet.
Metrology institute by Ciro Santilli 37 Created 2024-12-13 Updated 2025-07-16
Metrology by Ciro Santilli 37 Created 2024-12-13 Updated 2025-07-16
Type of prime number by Ciro Santilli 37 Created 2024-12-13 Updated 2025-07-16
This section is about prime numbers that satisfy further properties beyond just being a prime.
The Mystery of Matter by Ciro Santilli 37 Created 2024-12-13 Updated 2025-07-16
Very good documentary! Explains things very well! Great acting and wardrobe too.
Particularly tasteful is their choice of native speaker actors who speak their native language for less important narration, and English with an accent for more important moments, in particular when talking solo to the camera.
Video 1.
The Mystery of Matter episode 1
. Source.
Video 2.
The Mystery of Matter episode 2
. Source. Covers:
Video 3.
The Mystery of Matter episode 3
. Source.
Landau's problems by Ciro Santilli 37 Created 2024-12-13 Updated 2025-07-16
Generate random text in PostgreSQL by Ciro Santilli 37 Created 2024-12-05 Updated 2025-07-16
This one is good: stackoverflow.com/questions/36533429/generate-random-string-in-postgresql/44200391#44200391 as it also describes how to generate multiple values.
with symbols(characters) as (VALUES ('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'))
select string_agg(substr(characters, (random() * (length(characters) - 1) + 1)::INTEGER, 1), '')
from symbols
join generate_series(1,8) as word(chr_idx) on 1 = 1 -- word length
join generate_series(1,10000) as words(idx) on 1 = 1 -- # of words
group by idx;
Then you can insert it into a row with:
create table tmp(s text);
insert into tmp(s)
  select s from
  (
    with symbols(characters) as (VALUES ('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'))
    select string_agg(substr(characters, (random() * (length(characters) - 1) + 1)::INTEGER, 1), '') as asdf
    from symbols
    join generate_series(1,8) as word(chr_idx) on 1 = 1 -- word length
    join generate_series(1,10000) as words(idx) on 1 = 1 -- # of words
    group by idx
  ) as sub(s);
A more convenient approach is likely to define the function:
CREATE OR REPLACE FUNCTION random_string(int) RETURNS TEXT as $$
select
  string_agg(substr(characters, (random() * length(characters) + 1)::integer, 1), '') as random_word
from (values('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789    --')) as symbols(characters)
  join generate_series(1, $1) on 1 = 1
$$ language sql;
And then:
create table tmp(s text, t text);
insert into tmp(s) select random_string(10) from generate_series(10);
This section is about converting: www.gutenberg.org/ebooks/10, and most likely the plaintext version: stackoverflow.com/a/43060761/895245 to the same data format as www.kaggle.com/datasets/oswinrh/bible mapping book/chapter/verse to the text:
1 1 1 In the beginning God created the heaven and the earth.
1 1 2 And the earth was without form, and void; and darkness was upon the face of the deep.
On particular annoyance is that the txt version has multiple verses per line at times.
We'd likely just want to use a slightly modified version of: stackoverflow.com/a/43060761/895245 that searches for patterns of type:
(\d+):(\d+)
with incremental integers.
Visible Human Project by Ciro Santilli 37 Created 2024-12-04 Updated 2025-07-16
Frozen and cut on Microtome at 1mm intervals.
Human biology database by Ciro Santilli 37 Created 2024-12-04 Updated 2025-07-16
All DVSA materials should be free by Ciro Santilli 37 Created 2024-12-04 Updated 2025-07-16
It is obscene that the DVSA, which is the UK organ that officially setups up the theory driving tests, does not make all of its material open.
As such, it uses its monopoly on the test as an advantage to sell books and services that allow you to pass the tests.
Particularly obscene is their focus on an online service: www.safedrivingforlife.info/shop/official-dvsa-theory-test-kit-car-drivers-elearning (archive) a that you can only use for 30 days and costs 15 pounds as of 2024. This way you can't even buy the book used or go to a library.
Obscene.
Paying to take the test is fine. But paying for learning materials which help everyone become better drivers and saves lives? Obscene.
Driver and Vehicle Standards Agency by Ciro Santilli 37 Created 2024-12-04 Updated 2025-07-16
The UK organ responsible for granting driving licenses.
Virtual Worm Project by Ciro Santilli 37 Created 2024-12-04 Updated 2025-07-16
This one has a 3D model of C. elegans containing all the cells, browsable on the browser at: browser.openworm.org/.
https://web.archive.org/web/20240928210212im_/http://caltech.wormbase.org/virtualworm/Images/OpenWormBrowser3.png

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