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.
Learn in public Updated 2025-07-16
This is the most extreme and final form of peer tutoring, it's natural final consequence given the Internet Age.
Lebesgue integral of is complete but Riemann isn't Updated 2025-07-16
is:
- complete under the Lebesgue integral, this result is may be called the Riesz-Fischer theorem
- not complete under the Riemann integral: math.stackexchange.com/questions/397369/space-of-riemann-integrable-functions-not-complete
And then this is why quantum mechanics basically lives in : not being complete makes no sense physically, it would mean that you can get closer and closer to states that don't exist!
Bloons Tower Defense 5 Updated 2025-07-16
One of Ciro Santilli's favorites.
Blue (university sport) Updated 2025-07-16
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
Bohr-Sommerfeld model Updated 2025-07-16
Refinement of the Bohr model that starts to take quantum angular momentum into account in order to explain missing lines that would have been otherwise observed TODO specific example of such line.
They are not observe because they would violate the conservation of angular momentum.
Introduces the azimuthal quantum number and magnetic quantum number.
Browser MMORPG Updated 2025-07-16
Browse S3 bucket on web browser Updated 2025-07-16
They can't even make this basic stuff just work!
Fabless semiconductor company Updated 2025-07-16
Circuit-based quantum computer Updated 2025-07-16
Lawrence Livermore National Laboratory Updated 2025-07-16
Founded partly due to the influence of Edward Teller who thought Los Alamos National Laboratory was not making good progress on thermonuclear weapons, large part of which was developed there.
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 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
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.
Butterfly dream Updated 2025-07-16
Chapter 2 paragraph 14:
Formerly, I, Zhuang Zhou, dreamt that I was a butterfly, a butterfly flying about, feeling that it was enjoying itself. I did not know that it was Zhou. Suddenly I awoke, and was myself again, the veritable Zhou. I did not know whether it had formerly been Zhou dreaming that he was a butterfly, or it was now a butterfly dreaming that it was Zhou. But between Zhou and a butterfly there must be a difference. This is a case of what is called the Transformation of Things.'
C3 Oxford physics course Updated 2025-07-16
- web.archive.org/web/20170907092044/http://www2.physics.ox.ac.uk/students/course-materials/c3-condensed-matter-major-option it wasn't paywalled in the past up to 2017, but later became. Bastards.
- www2.physics.ox.ac.uk/sites/default/files/page/2011/10/04/c3-intro-vacprobs17-41753.pdf gives the 2016 structure:
- Crystal Structure & Dynamics 10 lectures Dr Roger Johnston
- Band Theory 10 lectures Prof Michael Johnston
- Magnetism 7 lectures Prof Radu Coldea
- Optical Properties 6 lectures Prof Laura Herz
- Superconductivity 7 lectures Dr Peter Leek and Dr Amalia Coldea. web.archive.org/web/20170912021658/http://www2.physics.ox.ac.uk/sites/default/files/page/2011/10/04/cmpsc-handout-2017-41006.pdf
Cabbage (Csound) Updated 2025-07-16
Caenorhabditis elegans Updated 2025-07-16
- www.cell.com/cell-systems/fulltext/S2405-4712(16)30120-X
- www.cell.com/cell-systems/fulltext/S2405-4712(16)30151-X A Genome-Scale Database and Reconstruction of Caenorhabditis elegans Metabolism Gebauer, Juliane et al. Cell Systems , Volume 2 , Issue 5 , 312 - 322
Caesium standard Updated 2025-07-16
Uses the frequency of the hyperfine structure of caesium-133 ground state, i.e spin up vs spin down of its valence electron , to define the second.
International System of Units definition of the second since 1967, because this is what atomic clocks use.
TODO why does this have more energy than the hyperfine split of the hydrogen line given that it is further from the nucleus?
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.: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".
- : another positive definite symmetric bilinear form such as ?
- what if we drop the positive definite requirement, e.g. ?
There are unlisted articles, also show them or only show them.