{c}
{wiki}

Linear combination of a <Dirichlet boundary condition> and <Neumann boundary condition> at each point of the boundary.

Examples:
* <heat equation> when metal plaque is immersed in a large external environment of fixed temperature.

  In this case, the normal derivative at the boundary is proportional to the difference between the temperature of the boundary and the fixed temperature of the external environment.

  The result as time tends to infinity is that the temperature of the plaque tends to that of the environment.

  Shown a solved example in the <FreeFem> tutorial: https://doc.freefem.org/tutorials/thermalConduction.html (https://github.com/FreeFem/FreeFem-doc/blob/1d5996d8b891fd553fd318321249c2c30f693fc3/source/tutorials/thermalConduction.rst)


Robin boundary condition

* http://www.eng.fsu.edu/~dommelen/quantum/style_a/index.html
* https://web.archive.org/web/20200220003741/http://www.eng.fsu.edu/~dommelen/quantum/style_a/index.html

Looks very impressive! Last update marked 2011 as of 2020.

Goes up to "A.15 <quantum field theory> in a Nanoshell", Ciro have to review it to see if there's anything worthwhile in that section.

Personal page says he retired as of 2020: http://www.eng.fsu.edu/~dommelen/ But hopefully he has more time for these notes!

And he appears to have his own lightweight markup language that <transpiles> to <LaTeX> called l2h: http://www.eng.fsu.edu/~dommelen/l2h/


Quantum Mechanics for Engineers by Leon van Dommelen (2011)

Although quotients look a bit real number division, there are some important differences with the "group analog of multiplication" of <direct product of groups>.

If a group is isomorphic to the <direct product of groups>, we can take a quotient of the product to retrieve one of the groups, which is somewhat analogous to division: https://math.stackexchange.com/questions/723707/how-is-the-quotient-group-related-to-the-direct-product-group

The "converse" is not always true however: a group does not need to be isomorphic to the product of one of its <normal subgroups> and the associated <quotient group>. The wiki page provides an example:
\Q[Given G and a normal subgroup N, then G is a group extension of G/N by N. One could ask whether this extension is trivial or split; in other words, one could ask whether G is a direct product or semidirect product of N and G/N. This is a special case of the extension problem. An example where the extension is not split is as follows: Let $G = Z4 = {0, 1, 2, 3}$, and $ = {0, 2}$ which is isomorphic to Z2. Then G/N is also isomorphic to Z2. But Z2 has only the trivial automorphism, so the only semi-direct product of N and G/N is the direct product. Since Z4 is different from Z2 × Z2, we conclude that G is not a semi-direct product of N and G/N.]

TODO find a less minimal but possibly more important example.

This is also semi mentioned at: https://math.stackexchange.com/questions/1596500/when-is-a-group-isomorphic-to-the-product-of-normal-subgroup-and-quotient-group

I think this might be equivalent to why the <group extension problem> is hard. If this relation were true, then taking the direct product would be the only way to make larger groups from normal subgroups/quotients. But it's not.


Relationship between the quotient group and direct products

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

List of cards with images: https://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: https://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>{parent}.

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


Magic the gathering's banning of 7 cards due to "racism" (2020)

{wiki}

Basically what <register transfer level> compiles to in order to achieve a real chip implementation.

After this is done, the final step is <place and route>.

They can be designed by third parties besides the <semiconductor fabrication plants>. E.g. <Arm Ltd.> markets its <Arm Artisan>[Artisan] Standard Cell Libraries as mentioned e.g. at: https://web.archive.org/web/20211007050341/https://developer.arm.com/ip-products/physical-ip/logic This came from a 2004 acquisition: https://www.eetimes.com/arm-to-acquire-artisan-components-for-913-million/[], <if a product of a big company has a catchy name it came from an acquisition>[obviously].

The standard cell library is typically composed of a bunch of versions of somewhat simple gates, e.g.:
* AND with 2 inputs
* AND with 3 inputs
* AND with 4 inputs
* OR with 2 inputs
* OR with 3 inputs
and so on.

Each of those gates has to be designed by hand as a <3D> structure that can be produced in a given <fab>.

Simulations are then carried out, and the electric properties of those structures are characterized in a standard way as a bunch of tables of numbers that specify things like:
* how long it takes for electrons to pass through
* how much heat it produces
Those are then used in <power, performance and area> estimates.


Standard cell library

{wiki}

= Programming
{synonym}

Programming is hard. To <Ciro Santilli>, it's almost masochistic.

What makes Ciro especially mad when programming is not the hard things.

It is the things that should be easy, but aren't, and which take up a lot of your programming time.

Especially when you are already a few levels of "simple problems" down from your original goal, and another one of them shows up.

This is basically the cause of <Hofstadter's law>.

But of course, it is because it is hard that it feels amazing when you achieve your goal.

Putting a complex and useful program together is like composing a symphony, or reaching the summit of a hard <rock climbing> proble.

Programming can be an <art> form. There can be great beauty in code and what it does. It is a shame that this is hard to see from within the walls of most <companies>, where you are stuck doing a small specific task as fast as possible.


Computer programming

{c}
{wiki}

* <moving magnet and conductor problem>: the more experiments confirm <Maxwell's equations>, the more special relativity has to be correct
* <aberration (astronomy)> TODO more precisely how it is evidence.


Special relativity experiment

Jack Barsky

{wiki}

Obviously coupled with measures to prevent <capital flight>. This would be a required step to achieve <Ciro Santilli>'s dream of <unconditional basic income>.

Why don't the poor vote in mass for it is incomprehensible considering e.g. the <wealth inequality in the United States> as of 2020!
* https://www.jstor.org/stable/20027743?seq=1\#metadata_info_tab_contents
* https://www.washingtonpost.com/news/monkey-cage/wp/2018/02/27/why-the-poor-dont-vote-to-soak-the-rich/

Perhaps the election of <Donald Trump> in 2016 woke up the <democrats> at last, that they were just making empty promises without actually benefiting the poor? https://www.vox.com/2019/3/19/18240377/estate-tax-wealth-tax-70-percent-warren-sanders-aoc[]. Or is just another facade?

Bibliography:
* https://www.npr.org/sections/money/2019/02/26/698057356/if-a-wealth-tax-is-such-a-good-idea-why-did-europe-kill-theirs If a Wealth Tax is Such a Good Idea, Why Did <Europe> Kill Theirs?
* https://www.youtube.com/watch?v=XzonR81vVzM The Mayfair Set, Episode 2 - Entrepreneur Spelt S.P.I.V. (1999) by <Adam Curtis> explains nicely how in the 60's, https://en.wikipedia.org/wiki/Jim_Slater_(accountant)[Jim Slater] bought stock of inefficient companies, and sold off inefficient assets to make a profit.

  He managed to do that because previously people had regarded those companies as family companies, and never looked into the fact that they families weren't actually majority shareholders anymore.

  While this increased efficiency, it also fired many people, and the government didn't manage to change legislation fast enough to <tax> those profits to increase welfare.


Wealth tax

List of technology companies

As of 2020s and much earlier, <Ciro Santilli> believes that <undergrad> studies were fundamentally broken (considering the <Information Age> which completely changed what would be possible) because university had only two goals, with the exception of a few enlightened professors:
* rank students from worse to best so they can get into <PhD> programs.

  For regular jobs grades didn't even matter as much compared the prestige of your university (and therefore, <university entry exam> grades) and your ability to stand the stress of exams to get minimal passing grade.

  In particular, being able to rank requires setting the difficulty level at a point where you can see a <Normal distribution> in grades, and not have everyone at either 0 nor 100%.

  Also, this split could be caused by either shitty learning materials/conditions, or by mere volume. It doesn't matter.
* get money from the students. Of course, in countries where university is "free", this means reporting how many students you had to some government office so they can give you a corresponding budget. But you still have an incentive to enroll as many as possible.
As a result, most students, who would not go on to do a <PhD> essentially do a simple trade: all their time, and possibly some money, in exchange for embuing themselves with the incredible name of a respected institution so they can get better jobs later on.

Beauty, deep understanding, and learning awesome things comes basically as a second thought.


University should focus on inspiring and not on evaluating

Besides of course <the main function of university is sexual selection>[sexual selection], considering in this section only "formal learning" activities.

Consider e.g. the 2020 <University of Oxford>, where many many people are taking courses without any <laboratory> work (and also without much use at all) like literature and history, and they are paying about 9k <pounds>/year for it: <how much it costs to study at the University of Oxford?>.

Basically all of this could be done <OurBigBook.com>[online from books].

Laboratories are impossible however, because expendables of every experiment you do cost from hundreds to thousands of dollars, not to mention crazy upfront equipment costs.

For this reason, the brick and mortar aspect universities should focus exclusively on laboratories, and ensuring that the students with the most relevant knowledge (which can be readily obtained online) get access to those laboratories. Students should of course fully master every aspect of theory pertinent to their experiments. <principal investigators> should hand pick whichever criteria they want to select their students, possibly based partly on <exam as a service> if they find it a useful metric.

Furthermore, the use of laboratories should put great focus on <novel research>. A lot of laboratory instruction could be done from video of an experiments. As much as possible, we should use laboratories for novel research. Related: <videos of all key physics experiments>{full}.


The only reason for universities to exist should be the laboratories

{c}
{tag=JavaScript}

* \a[js/confirm-close.html]: https://stackoverflow.com/questions/7317273/warn-user-before-leaving-web-page-with-unsaved-changes
* \a[web-cheat/js-image-load.html]: load an image from JavaScript dynamically: https://stackoverflow.com/questions/226847/what-is-the-best-javascript-code-to-create-an-img-element
* \a[web-cheat/js-image-load-viewport.html]: load an image from JavaScript dynamically when it would become visible on the viewport: https://stackoverflow.com/questions/2321907/how-do-you-make-images-load-only-when-they-are-in-the-viewport
* \a[html/img-load-lazy.html]: https://stackoverflow.com/questions/2321907/how-do-you-make-images-load-lazily-only-when-they-are-in-the-viewport/57389607\#57389607
* \a[web-cheat/esm.html]: ESM modules
  * \a[web-cheat/esm1.js]
  * \a[web-cheat/esm2.js]
* \a[js/keydown.html]: https://stackoverflow.com/questions/16006583/capturing-ctrlz-key-combination-in-javascript

External libraries
* Text editors
  * \a[web-cheat/monaco-editor.html]:
    * https://github.com/microsoft/monaco-editor
    * https://stackoverflow.com/questions/63179813/how-to-run-the-monaco-editor-from-a-cdn-like-cdnjs/63179814\#63179814
* Interactive HTML table sorting
  * \a[web-cheat/tablesort.html]: https://github.com/tristen/tablesort
  * \a[web-cheat/sortable.html]: https://github.com/HubSpot/sortable


JavaScript browser example

{disambiguate=wiki}
{c}
{title2=2019}

= golden.com
{synonym}
{title2}

Website: https://golden.com

April 2024: merged with some fraud protection thing, is it sill a Wiki? Unclear, seem sto have lost that aspect: https://twitter.com/judegomila/status/1783028847983956430

Social media:
* https://twitter.com/golden

https://techcrunch.com/2019/04/30/golden-launch/
\Q[To state the obvious: <Wikipedia> is an incredibly useful website, but Gomila pointed out that notable companies and technologies like SV Angel, Benchling, Lisk and Urbit don’t currently have entries. Part of the problem is what he called Wikipedia’s “arbitrary notability threshold,” where pages are deleted for not being notable enough. (This is also what happened years ago to the Wikipedia page about yours truly — which I swear I didn’t write myself.)]
Exactly! <Deletionism on Wikipedia> is so sad, and especially for companies. In particular e.g. <Ciro Santilli> tried to create a page for <PsiQuantum>, and it got reverted... and now golden has one of the largest <Google> hits for it: https://golden.com/wiki/PsiQuantum-PBDGXRA

TODO how do they do moderation?

As of April 2024
\Q[Login is currently disabled.]
Asked at: https://twitter.com/cirosantilli/status/1777250258235302233 Their last tweets were from August 2023, so maybe they just silently shutdown? Their name is too generic and hard to search for efficietnly...

They do have <knowledge graph> built-in which is cool.


Golden

{c}
{wiki}

Co-founder of <Apple>.

Is Jobs <evil>? Is he interesting? Undoubtedly.

https://www.folklore.org/ProjectView.py?project=Macintosh&characters=Steve%20Jobs[] has some good anecdotes about him.

<Ciro Santilli> is especially fond of: <Jobs and Wozniak's blue box>.

Good quotes:
* "Try to have a nice family life, have fun, save a little money." quote at: <don't be a pussy>{full} and the related <Jobs and Wozniak's blue box> attitude
* "Steve Jobs Insult Response" on <backward design>
* Steve Jobs Pixar office design philosophy: great ideas happen from chance meetings on corridors, not in board rooms: https://officesnapshots.com/2012/07/16/pixar-headquarters-and-the-legacy-of-steve-jobs/
* <Steve Jobs' 2005 Stanford Commencement Address>
* <Here's to the crazy ones>: Ciro would like to believe that this is mostly written by Jobs, but apparently it was just written by an advertisement agency. Good job though. 

You must watch this: <video Bill Gates vs Steve Jobs by Epic Rap Battles of History (2012)>.

Evil deeds:
* not recognizing own daughter for many years??? https://en.wikipedia.org/wiki/Lisa_Brennan-Jobs
* lying to <Steve Wozniak> about the 5000 dollar Atari bonus: https://web.archive.org/web/20110612071502/http://www.woz.org/letters/general/91.html
* not giving stock to early garage employees: https://www.businessinsider.com/steve-wozniak-gave-early-apple-employees-10-million-in-stock-2014-9 OK, not a <legal> obligation. But... love?


Steve Jobs

{c}
{wiki}

Nice looking and expensive operating system by <Apple>. <Ciro Santilli> believes that:
* if you want to be ripped off, just use <Microsoft Windows> which has more software available
* or if you want to attain <ourbigbook com/motivation>[Enlightenment], just use <Linux>, which is free and open source

The story of how OS X was ported to x86 from PowerPC with large initial work up to boot by a single man in the year 2000, John Kullmann, is really worth reading: https://www.quora.com/Apple-company/How-does-Apple-keep-secrets-so-well/answer/Kim-Scheinberg on <Quora>, see also:
* https://www.theregister.co.uk/2012/06/11/apple_project_marklar_secrets/
* https://en.wikipedia.org/wiki/Apple%27s_transition_to_Intel_processors


MacOS

{wiki}

= Primitive recursive
{synonym}

In intuitive terms it consists of all integer functions, possibly with multiple input arguments, that can be written only with a sequence of:
* variable assignments
* addition and subtraction
* integer comparisons and if/else
* <for loops>
``
for (i = 0; i < n; i++)
``
and such that `n` does not change inside the loop body, i.e. no <while loops> with arbitrary conditions.

`n` does not have to be a constant, it may come from previous calculations. But it must not change inside the loop body.

<Primitive recursive functions> basically include every integer function that comes up in practice. Primitive recursive functions can have huge complexity, and it strictly contains <EXPTIME>. As such, they mostly only come up in <foundation of mathematics> contexts.

The cool thing about <primitive recursive functions> is that the number of iterations is always bound, so we are certain that they terminate and are therefore <computable>.

This also means that there are necessarily functions which are not <primitive recursive>, as we know that there must exist <uncomputable> functions, e.g. the <busy beaver function>.

Adding unbounded <while loops> of course enables us to simulate arbitrary <Turing machines>, and therefore increases the <complexity class>.

More finely, there are <non-primitive total recursive functions>, e.g. most famously the <Ackermann function>.


Primitive recursive function

{c}
{tag=Evil}

Too restrictive. People should be able to make money from stuff.

The definition of "commercial" could also be taken in extremely broad senses, making serious reuse risky in many applications.

Notably, many <university> courses use it, notably <MIT OpenCourseWare>. Ciro wonders if it is because <academics> are wary of <industry>, or if they want to make money from it themselves. This reminds Ciro of a documentary he watched about the origins of one an early <web browsers> in some <American> university. And then that university wanted to retain copyright to make money from it. But the PhDs made a separate company nonetheless. And someone from the company rightly said something along the lines of:
\Q[The goal of <universities> is to help create companies and to give back to society like that. Not to try and make money from inventions.]
TODO source.

The GNU project does not like it either https://www.gnu.org/licenses/license-list.en.html\#CC-BY-NC[]:
\Q[
This license does not qualify as free, because there are restrictions on charging money for copies. Thus, we recommend you do not use this license for documentation.

In addition, it has a drawback for any sort of work: when a modified version has many authors, in practice getting permission for commercial use from all of them would become infeasible.
]

https://en.wikipedia.org/wiki/Creative_Commons_NonCommercial_license\#Defining_%22Noncommercial%22 also talks about the obvious confusion this generates: nobody can agree what counts as commercial or not!
\Q[In September 2009 Creative Commons published a report titled, "Defining 'Noncommercial'". The report featured survey data, analysis, and expert opinions on what "noncommercial" means, how it applied to contemporary media, and how people who share media interpret the term. The report found that in some aspects there was public agreement on the meaning of "noncommercial", but for other aspects, there is wide variation in expectation of what the term means.]


CC BY-NC-SA

{c}
{tag=Arm (company)}

= ARM instruction set
{c}
{synonym}

= ARM
{disambiguate=ISA}
{c}
{synonym}

This <ISA> basically completely dominated the <smartphone> market of the 2010s and beyond, but it started appearing in other areas as the end of <Moore's law> made it more economical logical for large companies to start developing their own semiconductor, e.g. <Google custom silicon>, <Amazon custom silicon>.

It is exciting to see ARM entering the <server>, <desktop> and <supercomputer> market circa 2020, beyond its dominant mobile position and roots.

<Ciro Santilli> likes <Ciro Santilli's self perceived creative personality>[to see the underdogs rise], and bite off dominant ones.

The excitement also applies to <RISC-V> possibly over ARM mobile market one day conversely however.

Basically, as long as were a huge company seeking to develop a <CPU> and able to control your own ecosystem independently of <Windows>' desktop domination (held by the need for backward compatibility with a billion end user programs), ARM would be a possibility on your mind.

* in 2020, the Fugaku supercomputer, which uses an ARM-based <Fujitsu> designed chip, because the number 1 fastest supercomputer in <TOP500>: https://www.top500.org/lists/top500/2021/11/

  It was later beaten by another <x86> supercomputer https://www.top500.org/lists/top500/2022/06/[], but the message was clearly heard.
* 2012 https://hackaday.com/2012/07/09/pedal-powered-32-core-arm-linux-server/ pedal-powered 32-core Arm Linux server. A <publicity stunt>, but still, cool.
* <AWS Graviton>


ARM architecture family

{c}
{wiki}

<Ciro Santilli> tried to https://en.wikipedia.org/w/index.php?title=Finite_field&type=revision&diff=1044934168&oldid=1044905041[add this example to Wikipedia], but it was reverted, so here we are, see also: <Deletionism on Wikipedia>{full}.

This is a good first example of a field of a <finite field of non-prime order>, this one is a <prime power> order instead.

$4 = 2^2$, so one way to represent the elements of the field will be the to use the 4 polynomials of degree 1 over <GF(2)>:
* 0X + 0
* 0X + 1
* 1X + 0
* 1X + 1

Note that we refer in this definition to anther field, but that is fine, because we only refer to fields of <prime> order such as <GF(2)>, because we are dealing with <prime powers> only. And we have already defined fields of prime order easily previously with <modular arithmetic>.

Over GF(2), there is only one <irreducible polynomial> of degree 2:
$$
X^2+X+1
$$

Addition is defined element-wise with <modular arithmetic> modulo 2 as defined over GF(2), e.g.:
$$
(1X + 0) + (1X + 1) = (1 + 1)X + (0 + 1) = 0X + 1
$$

Multiplication is done modulo $X^2+X+1$, which ensures that the result is also of degree 1.

For example first we do a regular multiplication:
$$
(1X + 0) \times (1X + 1) = (1 \times 1)X^2 + (1 \times 1)X + (0 \times 1)X + (0 \times 1) = 1X^2 + 1X + 0
$$

Without modulo, that would not be one of the elements of the field anymore due to the $1X^2$!

So we take the modulo, we note that:
$$
1X^2 + 1X + 0 = 1(X^2+X+1) + (0X + 1)
$$
and by the definition of modulo:
$$
(1X^2 + 1X + 0) \mod (X^2+X+1) = (0X + 1)
$$
which is the final result of the multiplication.

TODO show how taking a reducible polynomial for modulo fails. Presumably it is for a similar reason to why things fail for the prime case.


Title	Created	Updated
Robin boundary condition	1970-01-01	1970-01-01
Quantum Mechanics for Engineers by Leon van Dommelen (2011)	1970-01-01	1970-01-01
Relationship between the quotient group and direct products	1970-01-01	1970-01-01
Magic the gathering's banning of 7 cards due to "racism" (2020)	1970-01-01	1970-01-01
Standard cell library	1970-01-01	1970-01-01
Computer programming	1970-01-01	1970-01-01
Special relativity experiment	1970-01-01	1970-01-01
Jack Barsky	1970-01-01	1970-01-01
Wealth tax	1970-01-01	1970-01-01
List of technology companies	1970-01-01	1970-01-01
University should focus on inspiring and not on evaluating	1970-01-01	1970-01-01
The only reason for universities to exist should be the laboratories	1970-01-01	1970-01-01
JavaScript browser example	1970-01-01	1970-01-01
Golden	1970-01-01	1970-01-01
Steve Jobs	1970-01-01	1970-01-01
MacOS	1970-01-01	1970-01-01
Primitive recursive function	1970-01-01	1970-01-01
CC BY-NC-SA	1970-01-01	1970-01-01
ARM architecture family	1970-01-01	1970-01-01
GF(4)	1970-01-01	1970-01-01

Ciro Santilli (@cirosantilli, 32)