Ciro Santilli @cirosantilli 40

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Yitang Zhang's theorem Updated 2025-07-16

There are infinitely many primes with a neighbor not further apart than 70 million. This was the first such finite bound to be proven, and therefore a major breakthrough.

This implies that for at least one value (or more) below 70 million there are infinitely many repetitions, but we don't know which e.g. we could have infinitely many:

k, k + 2

or infinitely many:

k, k + 4

or infinitely many:

k, k + 6, 999, 999

or infinitely many:

k, k + 2 an d k, k + 4

but we don't know which of those.

The Prime k-tuple conjecture conjectures that it is all of them.

Also, if 70 million could be reduced down to 2, we would have a proof of the Twin prime conjecture, but this method would only work for (k, k + 2).

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Brain in a vat Updated 2025-07-16

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BrainSimII Updated 2025-07-16

github.com/FutureAIGuru/BrainSimII

The video from futureai.guru/technologies/brian-simulator-ii-open-source-agi-toolkit/ shows a demo of the possibly non open source version. They have a GUI neuron viewer and editor, which is kind of cool.

Machine Learning Is Not Like Your Brain by Charles Simon (2022)

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yolov5-pip Updated 2025-07-16

github.com/fcakyon/yolov5-pip

OK, now we're talking, two liner and you get a window showing bounding box object detection from your webcam feed!

python -m pip install -U yolov5==7.0.9
yolov5 detect --source 0

The accuracy is crap for anything but people. But still. Well done. Tested on Ubuntu 22.10, P51.

fcakyon/yolov5-pip webcam object detection demo by Ciro Santilli (2023)

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What happens to the definition of the orthogonal group if we choose other types of symmetric bilinear forms Updated 2025-07-16

We looking at the definition the orthogonal group is the group of all matrices that preserve the dot product, we notice that the dot product is one example of positive definite symmetric bilinear form, which in turn can also be represented by a matrix as shown at: Section "Matrix representation of a symmetric bilinear form".

By looking at this more general point of view, we could ask ourselves what happens to the group if instead of the dot product we took a more general bilinear form, e.g.:

$I_{2}$ : another positive definite symmetric bilinear form such as $(x_{1}, x_{2})^{T} (y_{1}, y_{2}) = 2 x_{1} y_{1} + x_{2} y_{2}$ ?
$I_{-}$ what if we drop the positive definite requirement, e.g. $(x_{1}, x_{2})^{T} (y_{1}, y_{2}) = - x_{1} y_{1} + x_{2} y_{2}$ ?

The answers to those questions are given by the Sylvester's law of inertia at Section "All indefinite orthogonal groups of matrices of equal metric signature are isomorphic".

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What poor countries have to do to get richer Updated 2025-07-16

Like all poor countries, Brazil's lack of money and scientific culture severely limit its ability to make technological and scientific advances.

While this sounds obvious, Ciro Santilli has felt it first hand since he moved from Brazil to Europe, and it is just shocking.

In the city of Santos for example, despite being a dream place from the natural point of view, it would be completely impossible to achieve any deep tech technical advance that impacts the world. In Europe however, there are several several places where this can happen.

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WhatsApp Updated 2025-07-16

Claimed to remove metadata from servers unless legally obliged to collect it: www.quora.com/Does-WhatsApp-store-messages-on-its-servers-or-is-all-deleted-after-delivery-and-only-stored-on-recipients-phones/answer/Ciro-Santilli

They've had a few breaches: www.whatsapp.com/security/advisories/

They claim to delete metadata: www.quora.com/Does-WhatsApp-store-messages-on-its-servers-or-is-all-deleted-after-delivery-and-only-stored-on-recipients-phones/answer/Ciro-Santilli

WhatsApp founder Jan Koum talks about their Journey by Roots (2017)

Source. Good talk, explains how everything happened in the perfect location at the perfect time: unemployed people who knew how to code, bought an iPhone, the next big platform, at its very beginning, they had just release the required push notifications API, and he travelled a lot and knew how much SMS sucked, especially international.

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Circuit-based quantum computer Updated 2025-07-16

Synonym to gate-based quantum computer/digital quantum computer?

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Fabless semiconductor company Updated 2025-07-16

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CIA 2010 covert communication websites / Breakthroughs Updated 2025-07-16

Some less-trivial breakthroughs:

finding 2013 DNS Census
CGI comms characterization
secure subdomain search on 2013 DNS Census let to a few hits
2013 DNS Census virtual host cleanup heuristic keyword searches was massive and led to many new ranges

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Software license that starts closed and becomes open once a certain amount of money is raised Updated 2025-07-16

This is an interesting licensing model that might just scale.

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Software with bad user interface Updated 2025-07-16

It is hard to pinpoint why, but the following useful software just feel bad for some reason:

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Stockfish CLI Updated 2025-10-14

www.maketecheasier.com/use-stockfish-cli-master-chess is a good source.

Most of what follows is part of the Universal Chess Interface. Tested on Ubuntu 22.10, Stockfish 14.1.

After starting stockfish on the command line, d (presumably display) contains:

 +---+---+---+---+---+---+---+---+
 | r | n | b | q | k | b | n | r | 8
 +---+---+---+---+---+---+---+---+
 | p | p | p | p | p | p | p | p | 7
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 6
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 5
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 4
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 3
 +---+---+---+---+---+---+---+---+
 | P | P | P | P | P | P | P | P | 2
 +---+---+---+---+---+---+---+---+
 | R | N | B | Q | K | B | N | R | 1
 +---+---+---+---+---+---+---+---+
   a   b   c   d   e   f   g   h

Fen: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
Key: 8F8F01D4562F59FB

Sweet ASCII art. where:

Fen: FEN notation
Key: TODO

Move white king's pawn from e2 to e4:

position startpos moves e2e4

Then display again:

gives:

 +---+---+---+---+---+---+---+---+
 | r | n | b | q | k | b | n | r | 8
 +---+---+---+---+---+---+---+---+
 | p | p | p | p | p | p | p | p | 7
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 6
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 5
 +---+---+---+---+---+---+---+---+
 |   |   |   |   | P |   |   |   | 4
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 3
 +---+---+---+---+---+---+---+---+
 | P | P | P | P |   | P | P | P | 2
 +---+---+---+---+---+---+---+---+
 | R | N | B | Q | K | B | N | R | 1
 +---+---+---+---+---+---+---+---+
   a   b   c   d   e   f   g   h

Fen: rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1
Key: B46022469E3DD31B

so we see that the pawn moved.

Now let's make Stockfish think for one second what is the next best move for black:

go movetime 1000

gives as the last line:

bestmove c7c5 ponder g1f3

what is ponder? Something to do with thinking on the opponent's turn: permanent brain.
understand the previous lines

To make the move it as suggested for black, we have to either repeat the entire sequence of movements:

position startpos moves e2e4 c7c5

d:

 +---+---+---+---+---+---+---+---+
 | r | n | b | q | k | b | n | r | 8
 +---+---+---+---+---+---+---+---+
 | p | p |   | p | p | p | p | p | 7
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 6
 +---+---+---+---+---+---+---+---+
 |   |   | p |   |   |   |   |   | 5
 +---+---+---+---+---+---+---+---+
 |   |   |   |   | P |   |   |   | 4
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   | 3
 +---+---+---+---+---+---+---+---+
 | P | P | P | P |   | P | P | P | 2
 +---+---+---+---+---+---+---+---+
 | R | N | B | Q | K | B | N | R | 1
 +---+---+---+---+---+---+---+---+
   a   b   c   d   e   f   g   h

Fen: rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2
Key: 4CA78BCE9C2980B0

or alternatively we could also use the previous FEN notation as a starting point;

position fen rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1 moves c7c5

Note how the Universal Chess Interface interface is very simple: we just load a state and then decide what to do next for that one state. The engine holds only one and exactly one state at a time, and you can't even modify it differentially without loading new one from scratch.

Let's move white again with our brain with either:

position startpos moves e2e4 c7c5 d2d3
position fen rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2 moves d2d3

Set a specific position from fen:

position fen rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1

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Bitcoin script Updated 2025-07-16

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bit gold Updated 2025-07-16

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2017 Nobel Prize in Chemistry Updated 2025-07-16

Cryogenic electron microscopy, which was developed in the 70's.

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1973 Nobel Prize in Physics Updated 2025-07-16

To Brian Josephson for the prediction of the Josephson effect.

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Black holes nearest to the Sun Updated 2025-07-16

Interesting to note that there are quite a few nearer than Sagittarius A, as of 2022 we know of one at 1.5 kly: universemagazine.com/en/discovered-the-closest-black-hole-to-the-sun/

It is interesting that a few months earlier there seemed to be no known specific black holes in the Milky Way: www.nasa.gov/feature/goddard/2022/hubble-determines-mass-of-isolated-black-hole-roaming-our-milky-way-galaxy although their count is estimated to be in the hundreds of millions.

For comparison, remember that the Milky Way is 185 kly in diameter x 2 kly thick.

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Phaser.js Updated 2025-07-16

Likely the best JavaScript 2D game engine as of 2023.

github.com/photonstorm/phaser
phaser.io/
phaser.io/examples/v3.85.0/games contains the demo games

Uses Matter.js as a physics engine if enabled. There's also an alternative (in-house?) "arcade" engine: photonstorm.github.io/phaser3-docs/Phaser.Physics.Arcade.ArcadePhysics.html but it appears to be simpler/less robust (but also possibly faster).

TODO any 2D first person examples a bit like Ciro's 2D reinforcement learning games?

The examples are present under:

git clone https://github.com/photonstorm/phaser3-examples

but note that that repo is huge, about 4.5 GiB on local disk, as is has tons of assets.

The demos also include a Monaco-editor based sandbox mode where you can edit code directly on the web and see the game update which is a really sweet addition.

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Phase transition Updated 2025-07-16

TODO can anything interesting and deep be said about "why phase transition happens?" physics.stackexchange.com/questions/29128/what-causes-a-phase-transition on Physics Stack Exchange

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 There are unlisted articles, also show them or only show them.