How to implement Nested set model in SQL:
- stackoverflow.com/questions/192220/what-is-the-most-efficient-elegant-way-to-parse-a-flat-table-into-a-tree/42781302#42781302 contains the correct left/size representation and update queries, which makes it much easier to maintain the tree without having to worry about the sizes of siblings which are constant
- stackoverflow.com/questions/192220/what-is-the-most-efficient-elegant-way-to-parse-a-flat-table-into-a-tree/194031#194031 amazing ASCII art representations of the structure. Unfortunately uses a wonky left/right representation, rather than the much more natural left/size representation from the other post
To avoid duplication when citing multiple pages: Section "How to use a single source multiple times in a Wikipedia article?"
A good big sample definition:There is also
<ref name="googleStory">{{cite book |last1=Vise |first1=David |author-link1=David A. Vise |last2=Malseed |first2=Mark |author-link2=Mark Malseed |title=The Google Story |date=2008 |publisher=Delacorte Press |url=https://archive.org/details/isbn_9780385342728}}</ref>title-link to link to a wiki page. But it is incompatible with url= for Internet Archive Open Library links which is a shame.So, it turns out that Wikipedia does have a (ultra obscure as usual) mechanism for pull requests. You learn a new one every day.
Handbook 2019/2020: web.archive.org/web/20210211192812/http://teaching.chem.ox.ac.uk/Data/Sites/58/media/courseinfo/ug-handbook-chemistry-2019-20.pdf
At teaching.chem.ox.ac.uk/undergraduate-course-handbook.aspx there's a paywall, but Google found the PDF it anyways.
www.ox.ac.uk/students/academic/guidance/undergraduate/handbooks in theory links to all handbooks, but some are likely paywalled. But Google can generally find them anyways.
Python sequence test data generation: stackoverflow.com/questions/18219779/bulk-insert-huge-data-into-sqlite-using-python/76659706#76659706
Example: sqlite/ip.c, adapted from www.sqlite.org/loadext.html, also mentioned explained at: stackoverflow.com/questions/7638238/sqlite-ip-address-storage/76520885#76520885.
Sample usage in the test program: sqlite/test.sh.
Process Simulation Software FREE Download - Aspen Hysys versus DWSim | COCO by Jeferson Costa (2020)
Source. Jeferson, a Brazilian from Petrobras, is the creator of the open source DWSim software, and in this video he gives a quick demo of his software and compares it briefly to aspen HYSYS, which appears to be the golden paid reference implementation.No, see: superconductor I-V curve.
Bibliography:
- physics.stackexchange.com/questions/62664/how-can-ohms-law-be-correct-if-superconductors-have-0-resistivity on Physics Stack Exchange
- physics.stackexchange.com/questions/69222/how-can-i-put-a-permanent-current-into-a-superconducting-loop
- www.quora.com/Do-superconductors-produce-infinite-current-I-V-R-R-0-How-do-they-fit-into-quantum-theory
- www.reddit.com/r/askscience/comments/dcgdf/does_superconductivity_imply_infinite_current/
- www.reddit.com/r/askscience/comments/7xhb46/what_would_happen_if_a_voltage_was_applied_to_a/
Superconducting Short Circuits across Batteries by Eugene Khutoryansky (2020)
Source. Well, internal battery resistance acts as the only resistor, and voltage drops to zero immediately outside of the battery. And you get a huge current.One thing to note is that Jimmy was a finance worker before starting wikipdia, e.g. he had capital to hire Larry Sanger.
Maybe that's the way to go about it, make money first, and later on change the world.
Starting just after the beginning of the Internet can't hurt either. Though tooling must have been insane back then.
____
The default isolation level for SQLite is SERIALIZABLE
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The default isolation level for SQLite is SERIALIZABLE
____
It does not appear possible to achieve the other two levels besides SERIALIZABLE and READ UNCOMMITED
Man-in-the-middle attack
quantumcomputing.stackexchange.com/questions/142/advantage-of-quantum-key-distribution-over-post-quantum-cryptography/25727#25727 Advantage of quantum key distribution over post-quantum cryptography has Ciro Santilli's comparison to classical encryption.
BB84 is a good first algorithm to look into.
Long story short:
- QKD allows you to generate shared keys without public-key cryptography. You can then use thses shared keys
- QKD requires authentication on a classical channel, exactly like a classical public-key cryptography forward secrecy would. The simplest way to do this is a with a pre-shared key, just like in classical public key cryptography. If that key is compromised at any point, your future messages can get man-in-the-middle'd, exactly like in classical cryptography.
QKD uses quantum mechanics stuff to allow sharing unsnoopable keys: you can detect any snooping and abort communication. Unsnoopability is guaranteed by the known laws of physics, up only to engineering imperfections.
Furthermore, it allows this key distribution without having to physically take a box by car somewhere: once the channel is established, e.g. optical fiber, you can just keep generating perfect keys from it. Otherwise it would be pointless, as you could just drive your one-time pad key every time.
However, the keys likely have a limited rate of generation, so you can't just one-time pad the entire message, except for small text messages. What you would then do is to use the shared key with symmetric encryption.
Therefore, this setup usually ultimately relies on the idea that we believe that symmetric encryption is safer than , even though there aren't mathematical safety proofs of either as of 2020.
Some examples by Ciro Santilli follow.
Of the tutorial-subjectivity type:
- This edit perfectly summarizes how Ciro feels about Wikipedia (no particular hate towards that user, he was a teacher at the prestigious Pierre and Marie Curie University and actually as a wiki page about him):which removed the only diagram that was actually understandable to non-Mathematicians, which Ciro Santilli had created, and received many upvotes at: math.stackexchange.com/questions/776039/intuition-behind-normal-subgroups/3732426#3732426. The removal does not generate any notifications to you unless you follow the page which would lead to infinite noise, and is extremely difficult to find out how to contact the other person. The removal justification is even somewhat ad hominem: how does he know Ciro Santilli is also not a professional Mathematician? :-) Maybe it is obvious because Ciro explains in a way that is understandable. Also removal makes no effort to contact original author. Of course, this is caused by the fact that there must also have been a bunch of useless edits not done by Ciro, and there is no reputation system to see if you should ignore a person or not immediately, so removal author has no patience anymore. This is what makes it impossible to contribute to Wikipedia: your stuff gets deleted at any time, and you don't know how to appeal it. Ciro is going to regret having written this rant after Daniel replies and shows the diagram is crap. But that would be better than not getting a reply and not learning that the diagram is crap.
rm a cryptic diagram (not understandable by a professional mathematician, without further explanations
- en.wikipedia.org/w/index.php?title=Finite_field&type=revision&diff=1044934168&oldid=1044905041 on finite fields with edit comment "Obviously: X ≡ α". Discussion at en.wikipedia.org/wiki/Talk:Finite_field#Concrete_simple_worked_out_example Some people simply don't know how to explain things to beginners, or don't think Wikipedia is where it should be done. One simply can't waste time fighting off those people, writing good tutorials is hard enough in itself without that fight.
- en.wikipedia.org/w/index.php?title=Discrete_Fourier_transform&diff=1193622235&oldid=1193529573 by user Bob K. removed Ciro Santilli's awesome simple image of the Discrete Fourier transform as seen at en.wikipedia.org/w/index.php?title=Discrete_Fourier_transform&oldid=1176616763:with message:
Hello. I am a retired electrical engineer, living near Washington,DC. Most of my contributions are in the area of DSP, where I have about 40 years of experience in applications on many different processors and architectures.
Thank you so much!!remove non-helpful image
Maybe it is a common thread that these old "experts" keep removing anything that is actually intelligible by beginners? Section "There is value in tutorials written by beginners"Also ranted at: x.com/cirosantilli/status/1808862417566290252
Figure 1. Ciro Santilli's awesome graph removed by Bob K. from the Discrete Fourier transform page.Source at: numpy/fft_plot.py. - when Ciro Santilli created Scott Hassan's page, he originally included mentions of his saucy divorce: en.wikipedia.org/w/index.php?title=Scott_Hassan&oldid=1091706391 These were reverted by Scott's puppets three times, and Ciro and two other editors fought back. Finally, Ciro understood that Hassan's puppets were likely right about the removal because you can't talk about private matters of someone who is low profile:even if it is published in well known and reliable publications like the bloody New York Times. In this case, it is clear that most people wanted to see this information summarized on Wikipedia since others fought back Hassan's puppet. This is therefore a failure of Wikipedia to show what the people actually want to read about.This case is similar to the PsiQuantum one. Something is extremely well known in an important niche, and many people want to read about it. But because the average person does not know about this important subject, and you are limited about what you can write about it or not, thus hurting the people who want to know about it.
Notability constraints, which are are way too strict:There are even a Wikis that were created to remove notability constraints: Wiki without notability requirements.
- even information about important companies can be disputed. E.g. once Ciro Santilli tried to create a page for PsiQuantum, a startup with $650m in funding, and there was a deletion proposal because it did not contain verifiable sources not linked directly to information provided by the company itself: en.wikipedia.org/wiki/Wikipedia:Articles_for_deletion/PsiQuantum Although this argument is correct, it is also true about 90% of everything that is on Wikipedia about any company. Where else can you get any information about a B2B company? Their clients are not going to say anything. Lawsuits and scandals are kind of the only possible source... In that case, the page was deleted with 2 votes against vs 3 votes for deletion.is very similar to Stack Exchange's own Stack Overflow content deletion issues. Ain't Nobody Got Time For That. "Ain't Nobody Got Time for That" actually has a Wiki page: en.wikipedia.org/wiki/Ain%27t_Nobody_Got_Time_for_That. That's notable. Unlike a $600M+ company of course.
should we delete this extremely likely useful/correct content or not according to this extremely complex system of guidelines"
In December 2023 the page was re-created, and seemed to stick: en.wikipedia.org/wiki/Talk:PsiQuantum#Secondary_sources It's just a random going back and forth. Author Ctjk has an interesting background:I am a legal official at a major government antitrust agency. The only plausible connection is we regulate tech firms
For these reasons reason why Ciro basically only contributes images to Wikipedia: because they are either all in or all out, and you can determine which one of them it is. And this allows images to be more attributable, so people can actually see that it was Ciro that created a given amazing image, thus overcoming Wikipedia's lack of reputation system a little bit as well.
Wikipedia is perfect for things like biographies, geography, or history, which have a much more defined and subjective expository order. But when it comes to "tutorials of how to actually do stuff", which is what mathematics and physics are basically about, Wikipedia has a very hard time to go beyond dry definitions which are only useful for people who already half know the stuff. But to learn from zero, newbies need tutorials with intuition and examples.
Bibliography:
- gwern.net/inclusionism from gwern.net:
Iron Law of Bureaucracy: the downwards deletionism spiral discourages contribution and is how Wikipedia will die.
- Quote "Golden wiki vs Deletionism on Wikipedia"
As usual, it is useful to think about how a bilinear form looks like in terms of vectors and matrices.
Unlike a linear form, which was a vector, because it has two inputs, the bilinear form is represented by a matrix which encodes the value for each possible pair of basis vectors.
There are unlisted articles, also show them or only show them.