Ciro Santilli @cirosantilli  40

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Permadeath Updated 2025-07-16

Dungeon Crawl Stone Soup Updated 2025-07-16

Appears to be the best classic open source roguelike of the 2020's.

This website is really cool! crawl.akrasiac.org:8080/#lobby You can spectate players live and chat! Also has statistics.

Devs of this game are smart, they have one good in-tree tileset, unlike some other text-based games that didn't have an in-tree option...

Build on Ubuntu 21.10:

sudo apt install build-essential libncursesw5-dev bison flex liblua5.1-0-dev \
libsqlite3-dev libz-dev pkg-config python3-yaml binutils-gold python-is-python3 \
libsdl2-image-dev libsdl2-mixer-dev libsdl2-dev libfreetype6-dev libpng-dev \
fonts-dejavu-core advancecomp pngcrush

git clone --depth 1 --branch 0.28.0 https://github.com/crawl/crawl
cd crawl/crawl-ref/source
echo 0.28-a > util/release_ver
make -j`nproc` TILES=y
./crawl

This launches the UI version already for you.

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Blaise Pascal (1972) Updated 2025-07-16

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IMDb: www.imdb.com/title/tt0066839/

Episodes of the life of Blaise Pascal.

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Cartesius (1974) Updated 2025-07-16

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IMDb: www.imdb.com/title/tt0161382/

This film is really good.

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Robert Noyce: The Man Behind the Microchip by Leslie Berlin (2006) Updated 2025-07-16

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Borrow from the Internet Archive for free: archive.org/details/manbehindmicroc000berl/page/n445/mode/2up

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L^{p}

is complete Updated 2025-07-16

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TODO

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Fourier basis is complete for

L^{2}

Updated 2025-07-16

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math.stackexchange.com/questions/316235/proving-that-the-fourier-basis-is-complete-for-cr-2-pi-c-with-l2-norm

Riesz-Fischer theorem is a norm version of it, and Carleson's theorem is stronger pointwise almost everywhere version.

Note that the Riesz-Fischer theorem is weaker because the pointwise limit could not exist just according to it:

l^{p}

norm sequence convergence does not imply pointwise convergence.

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Riemann hypothesis Updated 2025-07-16

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visualizing the Riemann hypothesis and analytic continuation by 3Blue1Brown (2016) is a good quick visual non-mathematical introduction is to it.

One of the Millennium Prize Problems and Hilbert's problems.

Video 1.

What is the Riemann hypothesis REALLY about? by HexagonVideos (2022)

Source.

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Replacement of master and slave terminology from technology Updated 2025-07-16

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The IETF was a notable one: www.nytimes.com/2021/04/13/technology/racist-computer-engineering-terms-ietf.html

developers.google.com/style/word-list (archive) Google's avoid word list is a masterclass in 2020's political correctness

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Magic the gathering's banning of 7 cards due to "racism" (2020) Updated 2025-07-16

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Official announcement: magic.wizards.com/en/articles/archive/news/depictions-racism-magic-2020-06-10

List of cards with images: www.hipstersofthecoast.com/2020/06/wizards-bans-7-cards-that-depict-racism-including-invoke-prejudice/

Invoke prejudice: depicts the Ku Klux Klan. Card's title clearly criticizes them "prejudice".
Stone-Throwing Devils: not sure about this one: boardgames.stackexchange.com/questions/54341/what-is-offensive-about-the-card-stone-throwing-devils
Cleanse: it does not seem to have any reference to black people, image depicts fantastic animals. There are hundreds of cards that talk about black since it is one of the 5 colors of magic.
Pradesh Gypsies: does not appear to suggest any bad things about gypsies, on the contrary
Jihad: does not appear to suggest any bad things about Islam, on the contrary
Imprison: depicts a black slave. Let's pretend it never happened.
Crusade: pretend it never happened

By Wizards of the Coast, parent company of Magic: The Gathering.

Reddit discussion: www.reddit.com/r/mtgfinance/comments/h0kb84/depictions_of_racism_in_magic_aka_invoke/

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Rockefeller family Updated 2025-07-16

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They were basically a Microsoft of their century. A little less monopolistic perhaps as countries believed they should own they natural resources, unlike their data.

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Principal investigator Updated 2025-07-16

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RC oscillator Updated 2025-07-16

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First watch: Video "Oscillators: RC, LC, Crystal by GreatScott! (2015)"

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LC oscillator Updated 2025-07-16

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Oscillator made of an LC circuit.

First watch: Video "Oscillators: RC, LC, Crystal by GreatScott! (2015)"

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Dirac equation Updated 2025-07-16

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Adds special relativity to the Schrödinger equation, and the following conclusions come basically as a direct consequence of this!

Experiments explained:

spontaneous emission coefficients.
fine structure, notably for example Dirac equation solution for the hydrogen atom
antimatter
particle creation and annihilation

Experiments not explained: those that quantum electrodynamics explains like:

Lamb shift
TODO: quantization of the electromagnetic field as photons?

The Dirac equation is a set of 4 partial differential equations on 4 complex valued wave functions. The full explicit form in Planck units is shown e.g. in Video 1. "Quantum Mechanics 12a - Dirac Equation I by ViaScience (2015)" at youtu.be/OCuaBmAzqek?t=1010:

i \partial_{t} ψ_{1} ψ_{2} ψ_{3} ψ_{4} = - i \partial_{x} ψ_{4} ψ_{3} ψ_{2} ψ_{1} + \partial_{y} - ψ_{4} ψ_{3} - ψ_{2} ψ_{1} - i \partial_{z} ψ_{3} - ψ_{4} ψ_{1} - ψ_{2} + m ψ_{1} ψ_{2} - ψ_{3} - ψ_{4}

(1)

Equation 1.

Expanded Dirac equation in Planck units

Then as done at physics.stackexchange.com/questions/32422/qm-without-complex-numbers/557600#557600 from why are complex numbers used in the Schrodinger equation?, we could further split those equations up into a system of 8 equations on 8 real-valued functions.

Video 1.

Quantum Mechanics 12a - Dirac Equation I by ViaScience (2015)

Source.

Video 2.

PHYS 485 Lecture 14: The Dirac Equation by Roger Moore (2016)

Source.

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Quantum field theory Updated 2025-07-16

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Theoretical framework on which quantum field theories are based, theories based on framework include:

so basically the entire Standard Model

The basic idea is that there is a field for each particle particle type.

E.g. in QED, one for the electron and one for the photon: physics.stackexchange.com/questions/166709/are-electron-fields-and-photon-fields-part-of-the-same-field-in-qed.

And then those fields interact with some Lagrangian.

One way to look at QFT is to split it into two parts:

deriving the Lagrangians of the Standard Model: S. This is the easier part, since the lagrangians themselves can be understood with not very advanced mathematics, and derived beautifully from symmetry constraints
the qantization of fields. This is the hard part Ciro Santilli is unable to understand, TODO mathematical formulation of quantum field theory.

Then interwined with those two is the part "OK, how to solve the equations, if they are solvable at all", which is an open problem: Yang-Mills existence and mass gap.

There appear to be two main equivalent formulations of quantum field theory:

Video 1.

Quantum Field Theory visualized by ScienceClic English (2020)

Source. Gives one piece of possibly OK intuition: quantum theories kind of model all possible evolutions of the system at the same time, but with different probabilities. QFT is no different in that aspect.

youtu.be/MmG2ah5Df4g?t=209 describes how the spin number of a field is directly related to how much you have to rotate an element to reach the original position
youtu.be/MmG2ah5Df4g?t=480 explains which particles are modelled by which spin number