{disambiguate=software}
{c}
{wiki}

Of course those racist <Nazis> are a bunch of idiots, but how can you be surprised when freedom-of-speech focused tech gets used by them? https://www.theverge.com/2019/7/12/20691957/mastodon-decentralized-social-network-gab-migration-fediverse-app-blocking

Obviously, a few large instances dominate the user base for all practical purposes: https://kevq.uk/centralisation-and-mastodon/[]. And likely the network splits into hate-speech/non-hate-speech blacklist boundaries. And since the dominating closed networks will never lose user counts (???), the only instance that dominates will be the main hate speech one.

The flagship instance was https://mastodon.social[] and then in 2020 they closed signups for it and created a secondary https://mastodon.online[].

The "advanced interface" feature is bad. Really bad. <MacOS> file browser inspired.


Mastodon

The exact format of table entries is fixed _by the hardware_.

Each page entry can be seen as a `struct` with many fields.

The page table is then an array of `struct`.

On this simplified example, the page table entries contain only two fields:
``
bits   function
-----  -----------------------------------------
20     physical address of the start of the page
1      present flag
``
so in this example the hardware designers could have chosen the size of the page table to b `21` instead of `32` as we've used so far.

All real page table entries have other fields, notably fields to set pages to read-only for Copy-on-write. This will be explained elsewhere.

It would be impractical to align things at 21 bits since memory is addressable by bytes and not bits. Therefore, even in only 21 bits are needed in this case, hardware designers would probably choose 32 to make access faster, and just reserve bits the remaining bits for later usage. The actual value on x86 is 32 bits.

Here is a screenshot from the Intel manual image "Formats of CR3 and Paging-Structure Entries with 32-Bit Paging" showing the structure of a page table in all its glory: <image x86 page entry format>{full}.

\Image[https://raw.githubusercontent.com/cirosantilli/media/master/x86_page_entry_format.png]
{height=300}
{title=x86 page entry format}

The fields are explained in the manual just after.


Page table entries

{c}
{wiki=Yang–Mills_existence_and_mass_gap}

* https://www.youtube.com/watch?v=-_qNKbwM_eE Unsolved: Yang-Mills existence and mass gap by J Knudsen (2019). Gives 10 key points, but the truly hard ones are too quick. He knows the thing though.

\Video[https://www.youtube.com/watch?v=j3fsPHnrgLg]
{title=Yang-Mills 1 by David Metzler (2011)}
{description=
Playlist: https://www.youtube.com/watch?v=j3fsPHnrgLg&list=PL613A31A706529585&index=13

A bit disappointing, too high level, with very few nuggests that are not Googleable withing 5 minutes.

Breakdown:
* 1 https://www.youtube.com/watch?v=j3fsPHnrgLg[]: too basic
* 2 https://www.youtube.com/watch?v=br6OxCLyqAI?t=569[]: mentions <groups of Lie type> in the context of <classification of finite simple groups>. Each group has a little diagram.
* 3 https://youtu.be/1baiIxKKQlQ?list=PL613A31A706529585&t=728 the original example of a <local symmetry> was <general relativity>, and that in that context it can be clearly seen that the local symmetry is what causes "forces" to appear
  * https://youtu.be/1baiIxKKQlQ?list=PL613A31A706529585&t=933 <local symmetry> gives a conserved current. In the case of <electromagnetism>, this is electrical current. This was the only worthwhile thing he sad to 2021 Ciro. Summarized at: <local symmetries of the Lagrangian imply conserved currents>.
* 4 https://youtu.be/5ljKcWm7hoU?list=PL613A31A706529585&t=427 <electromagnetism> has both a global symmetry (<special relativity>) but also <local symmetry>, which leads to the conservation of charge current and forces.

  <quantum field theory lecture by tobias osborne 2017/lecture 3> properly defines a <local symmetry> in terms of the context of the <lagrangian density>, and explains that the conservation of currents there is basically the statement of <Noether's theorem> in that context.
}
\Video[https://www.youtube.com/watch?v=vMiY7zlBOFI]
{title=Millennium Prize Problem: Yang Mills Theory by David Gross (2018)}
{description=2 hour talk at the <Kavli Institute for Theoretical Physics>. Too mathematical, 2021 Ciro can't make much out of it.}

\Video[https://www.youtube.com/watch?v=pCQ9GIqpGBI]
{title=Lorenzo Sadun on the "Yang-Mills and Mass Gap" <Millennium Prize Problems>[Millennium problem]}
{description=Unknown year. He almost gets there, he's good. Just needed to be a little bit deeper.}


Yang-Mills existence and mass gap

{wiki}

As https://en.wikipedia.org/w/index.php?title=ZX-calculus&oldid=1071329204\#Diagram_rewriting tries to explain <ourbigbook com/Wikipedia>[but fails to deliver as usual] consider the <GHZ state> represented as a quantum circuit.

How can we easily prove that that quantum circuit equals the state:
$$
\frac{|000> + |111>}{\sqrt{2}}
$$
?

The naive way would be to just do the matrix multiplication as explained at <quantum computing is just matrix multiplication>{full}.

However, ZX-calculus provides a simpler way.

And even more importantly, sometimes it is the only way, because in a real circuit, we would not be able to do the matrix multiplication 

What we do in ZX-calculus is we first transform the original quantum circuit into a ZX graph.

This is always possible, because we can describe how to do the conversion simply for any of the <Clifford plus T> gates, which is a set of <universal quantum gates>.

Then, after we do this transformation, we can start applying further transformations that simplify the circuit.

It has already been proven that there is no efficient algorithm for this (TODO source, someone said P-sharp complete best case)

But it has been proven in 2017 that any possible equivalence between quantum circuits can be reached by modifying ZX-calculus circuits.

There are only 7 transformation rules that we need, and all others can be derived from those, universality.

So, we can apply those rules to do https://en.wikipedia.org/w/index.php?title=ZX-calculus&oldid=1071329204\#Diagram_rewriting[the transformation shown in Wikipedia]:

\Image[https://upload.wikimedia.org/wikipedia/commons/0/05/GHZ_circuit_as_ZX-diagram.svg]
{height=500}
{title=GHZ circuit as ZX-diagram}

and one of those rules finally tells us that that last graph means our desired state:
$$
\frac{|000> + |111>}{\sqrt{2}}
$$
because it is a Z spider with $m = 3$ and $n = 1$.

\Video[https://www.youtube.com/watch?v=JafI_LZts2g]
{title=Working with <PyZX> by Aleks Kissinger (2019)}
{description=
This video appears to give amazing motivation on why you should care about <ZX-calculus>, it mentions
* <quantum compilation>
* <quantum computer simulation>
}

Bibliography:
* https://quantumcomputing.stackexchange.com/questions/9774/what-are-some-applications-of-the-zx-calculus


ZX-calculus

{c}
{wiki}

Split in the <spectral line> when a <magnetic field> is applied.

Non-anomalous: number of splits matches predictions of the <Schrödinger equation> about the number of possible states with a given angular momentum. TODO does it make numerical predictions?

<anomalous Zeeman effect>[Anomalous]: evidence of <spin (physics)>.

http://www.pas.rochester.edu/~blackman/ast104/zeeman-split.html contains the hello world that everyone should know: 2p splits into 3 energy levels, so you see 3 spectral lines from 1s to 2p rather than just one.

p splits into 3, d into 5, f into 7 and so on, i.e. one for each possible <azimuthal quantum number>.

It also mentions that polarization effects become visible from this: each line is polarized in a different way. TODO more details as in an experiment to observe this.

Well explained at: <video Quantum Mechanics 7a - Angular Momentum I by ViaScience (2013)>.

\Video[https://www.youtube.com/watch?v=ZmObNFAqkBE]
{title=Experimental physics - IV: 22 - Zeeman effect by Lehrportal Uni Gottingen (2020)}
{description=
This one is decent. Uses a <cadmium> lamp and an <etalon> on an <optical table>. They see a more or less clear 3-split in a circular <interference pattern>,

They filter out all but the transition of interest.

* https://youtu.be/ZmObNFAqkBE?t=165 passes the lines through a <polarizer>, which shows how orbital angular momentum is carried by <photon polarization>
* https://youtu.be/ZmObNFAqkBE?t=370 says they are looking at 1D2 to 1P1 changes.
}

\Video[https://www.youtube.com/watch?v=OzkcB1lkgGU]
{title=Zeeman Effect - Control light with magnetic fields by <Applied Science (YouTube channel)> (2018)}
{description=Does not appear to achieve a crystal clear split unfortunately.}


Zeeman effect

Talk by Ciro Santilli

{wiki}

Poet, scientists and warriors all in one? https://en.wikipedia.org/wiki/180_Degrees_South:_Conquerors_of_the_Useless[Conquerors of the useless].

A wise teacher from <University of São Paulo> once told the class <Ciro Santilli> attended an anecdote about his life:
\Q[
I used to want to learn Mathematics.

But it was very hard.

So in the end, I became an engineer, and found an engineering solution to the problem, and married a Mathematician instead.
]
It turned out that, about 10 years later, Ciro <Ciro Santilli's wife>[ended up following this advice], unwittingly.

\Image[https://web.archive.org/web/20190925220347if_/https://imgs.xkcd.com/comics/purity.png]
{disambiguate=mathematician}
{title=<xkcd> 435: Fields arranged by purity}
{source=https://xkcd.com/435/}


Mathematician

{c}

https://www.youtube.com/channel/UCu6mSoMNzHQiBIOCkHUa2Aw

This dude is <mind blowing>. Big respect.

Some of the most impressive videos are the ones in which he goes and extracts metals from minerals himself all the way.

But God, the typography of the channel name is so insane! Why no space???

Shame the academic system wasn't compatible with him: https://www.reddit.com/r/codyslab/comments/f5531p/codys_qualifications/ Maybe there were safety issues involved though.

\Video[https://www.youtube.com/watch?v=x1mv0vwb08Y]
{title=What's Been Going On With Cody'sLab? by <Cody'sLab> (2019)}
{description=Cody opening up about some issues he's having life. Notably: <being naughty and creative are correlated>.}


Cody'sLab

{tag=Image generation}

* https://digitalcommons.law.seattleu.edu/cgi/viewcontent.cgi?article=1585&context=sulr
* https://www.inverse.com/article/12948-computer-generated-vr-child-pornography-will-be-horrible-illegal-and-immersive
* https://www.crime-research.org/library/Illegal1.htm
* https://www.quora.com/Should-purely-computer-generated-imagery-CGI-of-child-pornography-be-illegal


Computer generated child pornography

{c}

Bought May 2024 to be my clean crypto-only computer. Searched for cheapest 1 TB disk 16 GB RAM not too old on Amazon with Ubuntu certification, and that was it at £479.00.
* https://www.dell.com/en-uk/shop/laptops-2-in-1-pcs/inspiron-15-laptop/spd/inspiron-15-3520-laptop/cn32043sc
* Core™ i5-1235U https://www.intel.com/content/www/us/en/products/sku/226266/intel-core-i51235u-processor-12m-cache-up-to-4-40-ghz-with-ipu/specifications.html Q1'22


Dell Inspiron 15 3520

{c}

The <P51> is a bit too heavy, and the battery could be better!

* Dell XPS 15 https://www.dell.com/en-uk/shop/laptops/12th-gen-intel/spd/xps-15-9520-laptop
  * CPU: Intel Core i7-12700H (12th gen)
  * Graphics: Nvidia GeForce RTX 3050 Ti
  * RAM: 16GB DDR5. Can be upgrated to 32 or 64.
  * Display: 15.6-inch 3.5K (3,456 x 2,160), 60Hz
  * Storage: 1TB PCIe NVMe M.2 SSD. Can be upgraded to 2TB or 4TB.
  * Weight: 1.96 kg
  * Price in UK: £1,948.99
  * Ubuntu: no
  * Tom's guide battery life: 10-hours (web browsing) https://www.tomsguide.com/reviews/dell-xps-15-oled-2022-review-a-great-macbook-pro-alternative
* Dell XPS 13 https://www.dell.com/en-uk/shop/laptops/xps-13/spd/xps-13-9315-laptop
  * CPU: Intel Core i5-1230U (12th gen)
  * Graphics: integrated
  * RAM: 8GB DDR5. Can be upgrated to 16 or 32
  * Display: 13.4-inch
  * Storage: 512 GB. Can be upgraded to 1 TB
  * Weight: 1.17 kg
  * Price in UK: £913.00
  * Ubuntu: yes
  * Tom's guide Battery life: 13 hours and 11 minutes https://www.tomsguide.com/reviews/dell-xps-13-2022
* Dell XPS 13 plus
  * https://www.digitaltrends.com/computing/dell-xps-13-plus-vs-xps-13/
  * Tom's guide battery life: 7 hours and 34 minutes
* ThinkPad X1 Carbon Gen 11 (14" Intel) https://www.lenovo.com/gb/en/p/laptops/thinkpad/thinkpadx1/thinkpad-x1-carbon-gen-11-(14-inch-intel)/len101t0049
  * Storage: 256 GB SSD. Can be upgraded to 1 TB
  * RAM: 16 GB (soldered)
  * Graphics: integrated
  * Price in UK: £2,020.00
  * Ubuntu: no


2023 laptop buy research

The website moved from <AsciiDoctor> to <OurBigBook Markup> in 2020, making this section mostly useless. But hey, history!

Ciro's website is powered by <GitHub Pages> and https://github.com/asciidoctor/jekyll-asciidoc[Jekyll Asciidoc].

The source code is located at: https://github.com/cirosantilli/cirosantilli.github.io

Build locally, watch for changes and rebuild automatically, and start a local server with:
``
git clone --recursive https://github.com/cirosantilli/cirosantilli.github.io
cd cirosantilli.github.io
bundle install
npm install
./run
``

Source: `./run`.

The website will be visible at: http://localhost:4000[].

Tested on the latest Ubuntu.

Publish changes to <GitHub Pages>:
``
git add -u
git commit -m 'make yourself look sillier'
./publish
``

Source: `./publish`.

GitHub forces us to use the master branch for the build output... so the actual source is in the branch `dev`.

Update the gems with:
``
bundle update
git add Gemfile.lock
git commit -m 'update gems'
``

His website was originally written in <markdown>, however those were deprecated in favour of <AsciiDoctor> when Ciro saw the light, rationale shown at: \a[markdown-style-guide#use-asciidoc]{external}

GitHub pages is chosen instead of a single page GitHub README.adoc for the following reasons:
* Ciro will want some unsupported extensions, notably mathematics, likely with <mathematics typesetting setup of Ciro Santilli's website>[KaTeX server side]:
  * https://github.com/asciidoctor/asciidoctor/pull/3338
  * https://stackoverflow.com/questions/11256433/how-to-show-math-equations-in-general-githubs-markdownnot-githubs-blog
  * https://g14n.info/2014/09/math-on-github-pages/
  * https://stackoverflow.com/questions/11256433/how-to-show-math-equations-in-general-githubs-markdownnot-githubs-blog
  * https://www.quora.com/How-can-I-combine-latex-and-markdown-in-GitHub
* when GitHub dies, Ciro's website URL still lives and retains the <PageRank>!


How to develop Ciro Santilli's website before the OurBigBook migration

Future self, answer these.

10 years:
* 2017-2027: did self-driving cars become big?
* 2017-2027: did virtual reality become big?

20 years
* 2018-2038: are <molecular biology technologies>[companies offering free full genome decoding] just to get your genomic data and sell it to pharma companies?

  Someone like Ciro then creates an open source genomic database funded by health organizations that publishes genomes + phenotypes <anonymously>. Genome to phenotype analytics go crazy big.

40 years:
* 2017-2057: was <Ciro's 2D reinforcement learning games>[human level AI reached] (by non-bio devices :-)), even if very slow?
* 2017-2057: <Ciro Santilli's campaign for freedom of speech in China>[did China become democratic]?
* 2018-2058: did impressive <brain-computer interfaces> show up?


Questions for Ciro Santilli's future self

https://quoteinvestigator.com/2017/09/25/progress/ on <Quote Investigator>.

From <Scientific Autobiography by Max Planck translated by Frank Gaynor (1949)>:
\Q[A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.]

\Image[https://web.archive.org/web/20220409192934im_/https://www.smbc-comics.com/comics/1449330284-20151205.png]
{title=How Math works by <SMBC Comics>}
{description=
An amazing representation of <Science makes progress funeral by funeral>. Steps:
* Step 1: Insight
* Step 2: Resistance
* Step 3: Debate
* Step 4: Additional decades of debate
* Step 5: Changing of the guard
* Step 6: Transmission to students
}
{source=https://www.smbc-comics.com/comic/progress}


Science makes progress funeral by funeral

{c}
{tag=Alan Watts}
{tag=Dream argument}

Goes along: if you could control your life multiple times to be perfect, you would eventually get tired of paradise, and you would go further and further into creating uncertain worlds with some suffering, until you would reach the current real world.

Very similar to <The Matrix (1999)> when Agent Smith talks about the failed https://matrix.fandom.com/wiki/Paradise_Matrix[Paradise Matrix] shown at https://www.youtube.com/watch?v=9Qs3GlNZMhY[]:
\Q[Did you know that the first Matrix was designed to be a perfect human world where none suffered, where everyone would be happy? It was a disaster. No one would accept the program. Entire crops were lost. Some believed that we lacked the programming language to describe your "perfect world". But I believe that, as a species, human beings define their reality through misery and suffering. So the perfect world was a dream that your primitive cerebrum kept trying to wake up from.]

\Video[https://youtube.com/watch?v=XlCZm-mz20M]
{title=<Alan Watts>' "The dream of life" talk}


Alan Watts controlled dream of life talk

{title2=$Field[X]$}
{wiki}

By default, we think of polynomials over the <real numbers> or <complex numbers>.

However, a polynomial can be defined over any other field just as well, the most notable example being that of a polynomial over a <finite field>.

For example, given the finite field of <order (algebra)> 9, $GP(3)$ and with elements $\{0, 1, 2\}$, we can denote polynomials over that ring as
$$
GP(3)[x]
$$
where $x$ is the variable name.

For example, one such polynomial could be:
$$
P(x) = 2x^4 + x^2 + 2
$$
and another one:
$$
Q(X) = x^3 + 2x^2 + 2
$$
Note how all the coefficients are members of the finite field we chose.

Given this, we could evaluate the polynomial for any element of the field, e.g.:
$$
P(0) = 2 (0 \times 0 \times 0 \times 0) + (0 \times 0) + 2 = 2
P(1) = 2 (1 \times 1 \times 1 \times 1) + (1 \times 1) + 2 = 2 (1) + 1 + 2 = 2
P(2) = 2 (2 \times 2 \times 2 \times 2) + (2 \times 2) + 2 = 2 (16 % 3) + (4 % 3) + 2 = 2 + 1 + 2 = 2
$$
and so on.

We can also add polynomials as usual over the field:
$$
P(x) + Q(x) = 2x^4 + x^3 + (1+2)x^2 + (2 + 2) = 2x^4 + x^3 + (0)x^2 + 1 = 2x^4 + x^3 + 1
$$
and multiplication works analogously.


Polynomial over a field

* how I met <Boitatech> people: <CIA 2010 covert communication websites>{full} trended on <Hacker News>
* what I'm doing now for one year: <OurBigBook>{full}
  * tech demo: https://www.youtube.com/watch?v=BR2dXeR5jt8
  * motivation
  * hacking is the epitome of "University is broken": arms race that evolves too fast for university to ever catch up
* my best random projects with some infosec aspect:
  * https://cirosantilli.com/cool-data-embedded-in-the-bitcoin-blockchain\#prayer-wars
  * https://github.com/cirosantilli/linux-kernel-module-cheat
  * https://github.com/cirosantilli/all-github-commit-emails
  * https://github.com/cirosantilli/stack-overflow-vote-fraud-script
  * https://ourbigbook.com/cirosantilli/facebook-profile-face-dump
  * https://github.com/cirosantilli/china-dictatorship


Aratu Week 4

{c}
{wiki}

Good place to hunt for <the beauty of mathematics>.


Lists of mathematical problems

{wiki}

<Surely You're Joking, Mr. Feynman> chapter An Offer You Must Refuse (a play on words on <The Godfather (1972)>) has an interesting historical mention from the early 1950s while at <Caltech>:
\Q[
The next day, I had the greatest luck in making a decision. God must have set it up to help me decide. I was walking to my office, and a guy came running up to me and said, "Hey, Feynman! Did you hear what happened? Baade found that there are two different populations of stars! All the measurements we had been making of the distances to the galaxies had been based on Cephid variables of one type, but there's another type, so the universe is twice, or three, or even four times as old as we thought!"

I knew the problem. In those days, the <age of Earth>[earth appeared to be older] than the universe. The earth was four and a half billion, and the universe was only a couple, or three billion years old. It was a great puzzle. And this discovery resolved all that: The universe was now demonstrably older than was previously thought. And I got this information right away - the guy came running up to me to tell me all this.
]


Age of the universe

{wiki}

* <prokaryote> models:
  * <E. Coli>{child}: the most well studied
  * <mycoplasma>: a very minimal <genus>, notable species: <Mycoplasma genitalium>{child}
* <eukaryote>
  * <S. cerevisiae>{child}: simplest <eukaryote> model. <Unicellular>.
  * <C. elegans>{child}: simplest <multicellular organism> model
  * <vertebrate>:
    * <Zebrafish>{child}: simplest vertebrate model
    * <mammal>:
      * <Mus musculus>{child}: simplest mammal model


Title	Created	Updated
Mastodon	1970-01-01	1970-01-01
Page table entries	1970-01-01	1970-01-01
Yang-Mills existence and mass gap	1970-01-01	1970-01-01
ZX-calculus	1970-01-01	1970-01-01
Zeeman effect	1970-01-01	1970-01-01
Talk by Ciro Santilli	1970-01-01	1970-01-01
Mathematician	1970-01-01	1970-01-01
Cody'sLab	1970-01-01	1970-01-01
Computer generated child pornography	1970-01-01	1970-01-01
Dell Inspiron 15 3520	1970-01-01	1970-01-01
2023 laptop buy research	1970-01-01	1970-01-01
How to develop Ciro Santilli's website before the OurBigBook migration	1970-01-01	1970-01-01
Questions for Ciro Santilli's future self	1970-01-01	1970-01-01
Science makes progress funeral by funeral	1970-01-01	1970-01-01
Alan Watts controlled dream of life talk	1970-01-01	1970-01-01
Polynomial over a field	1970-01-01	1970-01-01
Aratu Week 4	1970-01-01	1970-01-01
Lists of mathematical problems	1970-01-01	1970-01-01
Age of the universe	1970-01-01	1970-01-01
Model organism	1970-01-01	1970-01-01

Ciro Santilli (@cirosantilli, 32)