There are only boring exampes of taking an uncomputable language and converting it into a number?
This section is about companies that integrate parts and software from various other companies to make up fully working computer systems.
Public landing page: www.ox.ac.uk/admissions/undergraduate/courses/course-listing/computer-science
Course lists: www.cs.ox.ac.uk/teaching/courses/ True to form, courses appear to have identifiers, e.g. The "course materials" section of each course leads to courses.cs.ox.ac.uk/ which is paywalled by IP (accessible via Eduroam): TODO which system does it use? Some courses place their materials directly on "www.cs.ox.ac.uk", and when that is the case they are publicly accessible. So it is very much hit and miss. E.g. www.cs.ox.ac.uk/teaching/courses/2022-2023/quantum/index.html from Quantum Processes and Computation course of the University of Oxford has the assignments such as www.cs.ox.ac.uk/people/aleks.kissinger/courses/qpc2022/assignment1.pdf publicly visible, but e.g. www.cs.ox.ac.uk/teaching/courses/2022-2023/modelsofcomputation/ has nothing.
qi for the Quantum Information course of the University of Oxford rather than more arbitrary A1/A2/A3, B1/B2/B3, naming convention used by the Mathematics course of the University of Oxford and the Physics course of the University of Oxford, and URLs can either have years or not:- www.cs.ox.ac.uk/teaching/courses/qi/: no year: goes to latest
- www.cs.ox.ac.uk/teaching/courses/2023-2024/qi/: has year, fixed year. Disgraceful repetition of redundant 2023-2024, but OK.
Handbook:
- 2022:
- general www.cs.ox.ac.uk/files/13731/CS%20Handbook%20final.pdf
- Year 1 (Prelims): www.cs.ox.ac.uk/files/13794/Handbook%202022%20Part%20C%20-%20V1.3.pdf
- Year 2/3 (Parts A/B): www.cs.ox.ac.uk/files/13793/Handbook%202022%20Parts%20A%20&%20B%20V1.3.pdf There is some mixture on which courses can be taken on year 2 or 3. This also implies that they cannot have the usual A2/B2 naming scheme. They just don't have names instead mostly. It is also the most beautiful illustration of why you shouldn't do Compute Science at university: there's no depth to the subject. You can just take random courses and you learn it all quickly. Section "The only reason for universities to exist should be the laboratories".
- Year 2 has four mandatory core courses:
- Models of Computation
- Algorithms and Data Structures
- Compilers (mandatory for compsi, but not mathematics and computer science)
- Concurrent programming
- A only:
- Probability
- Hilary term
- Concurrent Programming (mandatory for compsi, but not mathematics and computer science)
- Quantum information
- Year 2 has four mandatory core courses:
- Year 4 (Part C): www.cs.ox.ac.uk/files/13794/Handbook%202022%20Part%20C%20-%20V1.3.pdf
- Michaelmas term
- Bayesian Statistical Probabilistic Programming
- Concurrent Algorithms and Data Structures
- Quantum Processes and Computation
- Computational Learning Theory
- Computational Biology
- Advanced Complexity Theory
- Graph Representation Learning
- Hilary term
- Advanced Security
- Database Systems Implementation
- Ethical Computing in Practice
- Law and Computer Science
- Quantum Software course of the University of Oxford
- Geometric Deep Learning
- Foundations of Self-Programming Agents
- Deep Learning in Healthcare
- Michaelmas term
Computer science course of the University of Oxford variant Updated 2024-12-15 +Created 1970-01-01
Official archive: dilbert.com/
Radio Wave Properties: Electric and Magnetic Dipole Antennae by Harvard Natural Sciences Lecture Demonstrations (2020)
Source. The dude lights bulbs on an antenna made of a single piece of copper, powered with EM radiation. Amazing.
Dipole antenna receiver animation
. Source. 
Dipole antenna transmitter animation
. Source. 
As per en.wikipedia.org/w/index.php?title=Semidirect_product&oldid=1040813965#Properties, unlike the Direct product, the semidirect product of two goups is neither unique, nor does it always exist, and there is no known algorithmic way way to tell if one exists or not.
This is because reaching the "output" of the semidirect produt of two groups requires extra non-obvious information that might not exist. This is because the semi-direct product is based on the product of group subsets. So you start with two small and completely independent groups, and it is not obvious how to join them up, i.e. how to define the group operation of the product group that is compatible with that of the two smaller input groups. Contrast this with the Direct product, where the composition is simple: just use the group operation of each group on either side.
Product of group subsets
So in other words, it is not a function like the Direct product. The semidiret product is therefore more like a property of three groups.
The semidirect product is more general than the direct product of groups when thinking about the group extension problem, because with the direct product of groups, both subgroups of the larger group are necessarily also normal (trivial projection group homomorphism on either side), while for the semidirect product, only one of them does.
Conversely, en.wikipedia.org/w/index.php?title=Semidirect_product&oldid=1040813965 explains that if , and besides the implied requirement that N is normal, H is also normal, then .
Smallest example: where is a dihedral group and are cyclic groups. (the rotation) is a normal subgroup of , but (the flip) is not.
Note that with the Direct product instead we get and not , i.e. as per the direct product of two cyclic groups of coprime order is another cyclic group.
TODO:
- why does one of the groups have to be normal in the definition?
- what is the smallest example of a non-simple group that is neither a direct nor a semi-direct product of any two other groups?
- github.com/deepmind/meltingpot TODO vs DeepMind Lab2D? Also 2D discrete. Started in 2021.
- github.com/deepmind/ai-safety-gridworlds mentioned e.g. at www.youtube.com/watch?v=CGTkoUidQ8I by Rober Miles
Creating Multimodal Interactive Agents from DeepMind by Two Minute Papers (2023)
Source. www.deepmind.com/blog/building-interactive-agents-in-video-game-worldsOpen-Ended Learning Leads to Generally Capable Agents by DeepMind (2021)
Short name: XLand. Whitepaper: www.deepmind.com/blog/generally-capable-agents-emerge-from-open-ended-play.For positive definite matrices only.
TODO application.
TODO speedup over algorithm for general matrices.
www.studentclustercompetition.us/ comments:
The HPCG benchmark uses a preconditioned conjugate gradient (PCG) algorithm to measure the performance of HPC platforms with respect to frequently observed but challenging patterns of computing, communication, and memory access. While HPL provides an optimistic performance target for applications, HPCG can be considered as a lower bound on performance. Many of the top 500 supercomputers also provide their HPCG performance as a reference.
- requires intense refrigeration to 15mK in dilution refrigerator. Note that this is much lower than the actual superconducting temperature of the metal, we have to go even lower to reduce noise enough, see e.g. youtu.be/uPw9nkJAwDY?t=471 from Video "Building a quantum computer with superconducting qubits by Daniel Sank (2019)"
- less connectivity, normally limited to 4 nearest neighbours, or maybe 6 for 3D approaches, e.g. compared to trapped ion quantum computers, where each trapped ion can be entangled with every other on the same chip
TODO synonym to analog quantum computer?
It is also possible to carry out quantum computing without qubits using processes with a continuous spectrum of measurement.
As of 2020, these approaches seem less developed/promising, but who knows.
These computers can be seen as analogous to classical non-quantum analog computers.
twitter.com/cryptograffiti (marked as joined March 2014)
Bitcoin blockchain image indexer and uploader. Uses fake P2PKH address.
At some point it stopped using Bitcoin mainline and moved to Bitcoin Cash instead: www.newsbtc.com/news/bitcoin/cryptograffiti-rejects-bitcoin-core-bch-now-available-payment-method/ and therefore became useless. Existing indexes seem to have been broken as well.
Also, based on the timing of Figure "Erich Erstu", this service may be responsible for a large part of the raw JPEG images present in the blockchain from block 416527 (2016) onwards. This is also suggested by the comments at Figure "Tank Man".
A Quantitative Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin gives the interesting insight that all its transactions seem to return change/fees to one or two given addresses, thus making it very easy to list all their uploads if they were consistent! So all we need are some starting points, which we have mostly due to ASCII mentions of the site on known inscriptions, all of which have a few common spent addresses at the very end:so we just have to solve get all Bitcoin transactions from and to a given address and we are done. Blockchair shows about 800 entries as of February 2024, between 4f94f97eb156b8563a213bb292314a0bd9c95b39afc521fc5965d050daab2a78 (2014-03-02) and ac5f4ea03597b43a72fb8ab42bd5384629f87f4f4abc534f38b8c15148ccaf9f (2017-10-12): blockchair.com/bitcoin/outputs?s=time(desc)&q=recipient(1MVpQJA7FtcDrwKC6zATkZvZcxqma4JixS)
- 4c903a377addab7c1e35a685d3dabc664199e406374b1e5ce2fc59e78fb5b754: 1MVpQJA7FtcDrwKC6zATkZvZcxqma4JixS
- 87aad85c6cd75a516789f364637d243c668e3424d031ae510e43c6edfe6ed206: 1MVpQJA7FtcDrwKC6zATkZvZcxqma4JixS
- c206e8fff656f07b27dac831ef9b956792bae4e76a2cb43f14f49f0298bf2c2f: 1MVpQJA7FtcDrwKC6zATkZvZcxqma4JixS
- ca4f11131eca6b4d61daf707a470cfccd1ef3d80a6f8b70f1f07616b451ca64e: 1MVpQJA7FtcDrwKC6zATkZvZcxqma4JixS
Other related transactions:
- tx 87aad85c6cd75a516789f364637d243c668e3424d031ae510e43c6edfe6ed206, block 474652 (2017-07-07) via cryptograffiti.info the default pandoc markdown pandoc.org/try markdown tutorial string! First, unseen in our ASCII dumps due to UTF-8 encoding::followed by:
Unicode test: `Ä Ö Õ Ü ä ö õ ü`.And if ends with:An h1 header ============ Paragraphs are separated by a blank line.Uploaded from http://cryptograffiti.info to demonstrate Markdown rendering.
TODO understand what these are:
- ae92dc4c31943955ad6e3e45a4eb0067f488fdd9aecca65c946460dd2a85488d
- 3020dbd7c850bf8c19ebacf670a2830fe50999a8b2560a202af21d536760eea4
- d65384a21cb1c327cc42416a0b1e2a78ad0296cb7a15312bdcd67ef169ecb309
- a3e3100d2b9a86e310430945c001df97a70626220a9e151208aecbb613f1f152
- a9c82ebc47fabd1eed7eeea7760d0a3c99288af3c3a17e396ec790fc280698a2
- 92bfd5c0fb0f24efa6ca568c4475f44e94dfc8d0d4d5da04dfafc6261bf17f45
- 73c22adb21b93f9220d00d2614a50350824be95b8ea966349e6f35fe5ac5537b
- 099c0fd06d18953c886121ff143ea0a20d0baf29999f424fa1ac707a81cf4987
- 3ad6677303fb6f700a4f2f977fe86e5324e0ddb0d3b33a649e513d7e88904e85
- 31a2ddaf4b146e021246e1f82e28121f5c9c8729620978309004515c7e559910
- adaae897fd286aefb64a69e88a53e9af17ee98611ea595c3c92d038f3274d723
- d8bf48e9ad3de62c695ff34a96e340912bd62e0a0282b94da6386b837c31a30d
These are of course likely all made by AtomSea & EMBII themselves while developing/testing their upload system.
They are also artsy peoeple themselves, and as pointed at twitter.com/AllenVandever/status/1563964396656812034 what they were doing was basicaly non-fungible token art, which became much much more popular a few years later around 2021.
The first upload that we could find at github.com/cirosantilli/bitcoin-inscription-indexer/tree/3f53e152ec9bb0d070dbcb8f9249d92f89effa70#atomsea-index was tx 44e80475dc363de2c7ee17b286f8cd49eb146165a79968a62c1c2c4cf80772c9 on block 272573 (2013-12-01) but it does not show on Bitfossil: bitfossil.org/44e80475dc363de2c7ee17b286f8cd49eb146165a79968a62c1c2c4cf80772c9/. This is was due to an upload bug explained by the following entry. By looking at the ASCII data at github.com/cirosantilli/bitcoin-inscription-indexer/blob/master/data/out/0272.txt#L449 that this is meant to contain the same content as the following message: a quote from the Bhagavad Gita, so this is definitely a bugged version of the following one.
The next one is bitfossil.org/c9d1363ea517cd463950f83168ce8242ef917d99cd6518995bd1af927d335828/ on block 272577 (2013-12-02). It actually shows on bifossil and it reads:followed by:The bug message is definitely a reference to the previous non-visible bugged upload bitfossil.org/4b72a223007eab8a951d43edc171befeabc7b5dca4213770c88e09ba5b936e17/, TODO understand exactly how they fucked up. This illustrates the beauty of the blockchain very well: unlike with version control, you don't just see selected snapshots: you see actual debug logs!!!
I WONDER WHAT HISTORY WILL THINK ABOUT THESE FIRST FEW BUGS...HA HA HA. NOBODY IS PERFECT.
He who regards
With an eye that is equal
Friends and comrades,
The foe and the kinsman,
The vile, the wicked,
The men who judge him,
And those who belong
To neither faction:
He is the greatest.
WeAreStarStuff.jpgThe third AtomSea & EMBII upload, and the first actual image.
Message:The image shows showingAtomSea and EMBII together, presumably photographed by this dude.
Photo etchin' test. #AtomSea #embii (photo by Travis Ehrich)
The filename is of course a reference to the quote/idea: We Are Made of Star-Stuff that was much popularized by Carl Sagan.
bitfossil.org/fac0b9a4f90414710b806fd286e020aea2404498946845ef3783f305dd4cd3a7 (2024-01-13) contains a crapped version with only AtomSea persent.
HugPuddle.jpgThe fourth AtomSea & EMBII upload, and the second image. Message:
HugPuddle Testing Apertus Disk Drive
And then finally we meet Chiharu, EMBII's partner, with her hair painted blond (she's Japanese): ILoveYouMore.jpg.
Then there are two undecoded ones TODO investigate:
Then Nelson-Mandela.jpg.
Then there's an approximation of pi as ASCII decimal fraction bitfossil.org/70fd289901bae0409f27237506c330588d917716944c6359a8711b0ad6b4ce76/ from block 273522 (2013-12-07):
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211055596446229489549303819644288109756659334461284756482337867831652712019091456485669234603486104543266482133936072602491412737245870066063155881748815209209628292540917153643678925903600113305305488204665213841469519415116094330572703657595919530921861173819326117931051185480744623799627495673518857527248912279381830119491298336733624406566430860213949463952247371907021798609437027705392171762931767523846748184676694051320005681271452635608277857713427577896091736371787214684409012249534301465495853710507922796892589235420199561121290219608640344181598136297747713099605187072113499999983729780499510597317328160963185950244594553469083026425223082533446850352619311881710100031378387528865875332083814206171776691473035982534904287554687311595628638823537875937519577818577805321712268066130019278766111959092164201989
tx b8b9f50a354166c46b69ecd47a0fbd20ee78c3471d2557bf275aff1b4cf4752d (2013-12-07) contains Where the Sidewalk Ends by Shel Silverstein. TODO find on bitfossil.org, toplevel, tx seemed like a likely toplevel, but not working: bitfossil.org/b8b9f50a354166c46b69ecd47a0fbd20ee78c3471d2557bf275aff1b4cf4752d
There is a place where the sidewalk ends
And before the street begins,
And there the grass grows soft and white,
And there the sun burns crimson bright,
And there the moon-bird rests from his flight
To cool in the peppermint wind.Let us leave this place where the smoke blows black
And the dark street winds and bends.
Past the pits where the asphalt flowers grow
We shall walk with a walk that is measured and slow,
And watch where the chalk-white arrowls go
To the place where the sidewalk ends.Yes we'll walk with a walk that is measured and slow,
And we'll go where the chalk-white arrows go,
For the children, they mark, and the children, they know
The place where the sidewalk ends.
tx 56768b30dec33bd284223d85c23087975e2360b3391d20d505aa59a5675e5379 (2013-12-13) TODO find on bitfossil.org has the cutest message:
Dear Aliens,Hey.Sincerely,
EMBII & AtomSeaMBII
tx 415c702759893c63b3a57a7d196b014e51b2a33d2396c74b8e71acfaff6b9360 (2013-12-14) contains a poem by 13th century Persian poet Rumi (TODO find bitfossil.org toplevel), starting with:Reproduced e.g. at: www.abuddhistlibrary.com/Buddhism/H%20-%20World%20Religions%20and%20Poetry/World%20Religions/Islam/Teachers/Rumi/My%20dear%20friend/Rumi%20-%20my%20dear%20friend.htm
My dear friend
never lose hope
when the Beloved
sends you away.
bitfossil.org/73ca50321147bac9010bec43d63f7f76857fe9ede240cc89710e28723fdb242f/ (2013-12-14) has message:and links to 3 .txt files
MULTIFILE SUPPORT TEST
1.txt, 2.txt, 3.txt containing single characters 1, 2, and 3.
CompressedLogo.png
. Source. 2013-12-20. Message:Possibly www.linkedin.com/in/colby-nelson-59b538207/.
Colby Nelson and myself burnt the midnight oils designing the APERTUS imagery last night....Thanks Colby for all your help.
Contains an Apertus logo which is used on bitfossil.org/ itself, presumably they were designing that logo.
Hidden surprises in the Bitcoin blockchain by Ken Shirriff (2014) Updated 2024-12-15 +Created 1970-01-01
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