The Eternal Doorman

I am trying to resurrect my work I did in Bolivia on using Standard ML to dynamically specify and compile its own basis library functions. Part of this involves 15,000 lines of auto-generated code. I was reading David MacQueen's story about  Luca Cardelli and the Early Evolution of ML  where he writes "Luca called his compiler versions “Poses” adopting a terminology from dance." I wish I had kept a copy of an e-mail I once sent, about twenty years ago now, to the FOM list replying to John McCarthy 's post about communicating with extra-terrestrial aliens using mathematics. It was about abstract representations of mathematics, and what we could reasonably expect the aliens to understand about our mathematics (see Sci-Movie Movie - UFO (2018) ). I thought it would look like a wild dance, the sort of thing you'd see if an alien landed on your lawn and did a wild dance in front of you.  Martin Davis (whose parents were from Łódź, Poland, I have just discovered) reje

From Feynman's book QED The Strange Theory of Light and Matter. Because the theory of quantum mechanics could explain all of chemistry and the various properties of substances, it was a tremendous success. But still there was the problem of the interaction of light and matter. That is, Maxwell's theory of electricity and magnetism had to be changed to be in accord with the new principles of quantum mechanics that had been developed. So a new theory, the quantum theory of the interaction of light and matter, which is called by the horrible name of "quantum electrodynamics," was finally developed by a number of physicists in 1929. But the theory was troubled. If you calculated something roughly, it would give a reasonable answer. But if you tried to compute it more accurately, you would find that the the correction you thought was going to be small (the next term in a series, for example) was in fact very large--in fact it was infinity! So it turned out that you couldn&

See  Thorsten Altenkirch - Defining Regular Expressions : he does something interesting to implement alt, I need to watch it again, ...  Here's a problem: what does this expression match?  I should try using Magma to generate the first few hundred words and see if it's anything obvious. See  Numberphile - Sophie Maclean on the Catalan Numbers : There's also something fishy going on in the eBPF. See this tweet of Richard Clegg's and   Buzzing Across Space - A Children's Guide to eBPF . Subscribe to Computerphile .

Timing! Or maybe just ubiquity? I don't  know. See bintrees (on page 92 [100 in the PDF ]) in the infuriating  Proofs and Types by Girard, Lafont and Taylor . At 5:07  it's not clear to me why she chose those particular edges. I guess it's that whatever four of the five edges she chooses, if she chooses the same ones every time, then the functional relation holds regardless of the element of the group of rotations to which it refers. But that doesn't really explain why: to do that you need some sort of constructive process like recursive subdivision ("step-by-step, either 'do nothing' or 'split') to generate the different triangulations. Similarly, with the interpretation as Dyck words , ... her characerisation of the Dyck words as an invariant, vis "They have the same number of Xs and Ys and , as you scan the string from left to right, at no point do you ever have more Xs than there are Ys before that" is clearly isomorphic to "the

 I just saw her post on Twitter and found this short clip: Then I found this, from October 6, 2020. What a lovely person!  Subscribe to Yoko Ono .

I had to use Google translate to get an idea of what this song is about. It's beautiful. Love is scary. I first heard about her from a sweet little German goth girl who used to hang out at the Kelsey Kerridge "climbing wall" in Cambridge. She was going through some rough stuff, I think. So was I, looking back. Subscribe to Gianna Nannini .

A late 20th birthday-present for Lewis Carroll. This is a talk he gave a few days ago at USC. The Temperley-Lieb algebra gives an amazing constructive proof which actually counts 3-colorings. It's an evaluation/reduction process. They were doing this the same year John Reynolds gave his tutorial “the application of the lambda calculus to programming languages”. See  Definitional Interpreters Revisted . Subscribe to Daniel Tubbenhauer .

This is interesting, but it makes me really sad. She is explaining how the whole cyber-security industry works (or doesn't). It's sad because people who have enough talent and technical skill to do this work (even if most of the people in the industry don't!) could be so much more profitably employed if they were working on actually creating something that does something useful, which we desperately need. Instead, this is what they do, presumably because nobody who actually wants to do the stuff we need has any money to pay them to do it. That looks like quite a good driving game, ...  If you want to see how languages and programming should be done, read the preface and introduction to  The Definition of Standard ML (Revised) : Then in the introduction: The point I'm trying to make is that language definition is a mathematical exercise, and takes the form of a series of mathematical definitions and proofs, and these objects are entirely formal, which means they have a d

I learned a lot from this! Subcribe to Karolina Żebrowska .

What a sound!! See  Amy Sandoval - For the love of synth . Support her on Patreon:  https://www.patreon.com/fazioelectric Subscribe to Fazio Electric .

Well, I got bored of learning to use git, ... so I listenened to her interview with John Chowning again, and discovered csound IDE:  https://ide.csound.com/  and one little applet in particular: Steven Yi's Realtime Audio Processing Example . This is just a little feedback loop and a reverb mixer with a 2 second delay, and it has some amazing effects. The weird thing was that it started mixing the sound from her interview and what Chowning was saying suddenly started taking on more significance: See her interview here:  Amy Sandoval Interview With John Chowning : See also  Colleen Fazio - Traynor YBA3 Custom Special  and note the aside about microphonics in the valve amplifier. That's a level of feedback you get in valve amps when the speaker in the case makes the heating elements in the valves resonate. That must have some interesting electro-acoustical effects on the formation of plasma inside the valves. I am also thinking about the sorts of systems that could exist in the

I'm trying to synthesize finite fields. What I am looking for is a way to use finite differences to approximate (i.e. synthesize) the complex exponential function to just the degree necessary for a given fidelity of representation. See e.g.  Finite-difference time-domain method . The time-dependent Maxwell's equations (in partial differential form) are discretized using central-difference approximations to the space and time partial derivatives. The resulting finite-difference equations are solved in either software or hardware in a leapfrog manner: the electric field vector components in a volume of space are solved at a given instant in time; then the magnetic field vector components in the same spatial volume are solved at the next instant in time; and the process is repeated over and over again until the desired transient or steady-state electromagnetic field behavior is fully evolved. See e.g. this Unity page:  Realtime Global Illumination using Enlighten . I looked at th

Oh crumbs, I hope she has enough to eat, ... She's trying to make me feel better, I think. See  Nathan on Kuratowski's 14 Set Theorem . Perhaps Nathan would be interested in the sets in Edmund Landau's century-old Riemann Hypothesis equivalent:  Daniel Tubbenhauer and Holly Krieger on The Riemann Hypothesis . See  Fractal Dimension - Cantor's Dust . Subscribe to Tibees .

For context, see A skeptical look at the Special Relativity narrative See  Steven Weinberg on Aristotle and Modern Science ,  Another Introduction to Geometric Algebra  and Wikipedia's  Introduction to gauge theory . See  Algebraic Topology of Finite Topological Spaces and Applications  by Jonathan A. Barmak The first chapter of this is surprisingly readable, and would be understandable too, to someone who is familiar with  CW complexes  and Homotopy theory in general. See also  How to Divide Without Floating Point Arithmetic  and  Norman Wildberger's Sociology of Mathematics . See also  Daniel Tubbenhauer and Holly Krieger on The Riemann Hypothesis . Subscribe to Cambridge Universiy Press . Subscribe to Numberphile . Maybe that number should be called Z ? See Doron Zeilberger - An Ultra-Finitistic Foundation of Probability (Foundations of Probability seminar November 19, 2018:) See  Opinion 165: The MASTERPIECE "Ten Great Ideas about Chance" by Persi Diaconis and Br

He does it in 6502 assembler at the end, ... on his BBC Emulator which has a very cool debugger too! See it here:  https://bbc.godbolt.org/  (but I can't figure out how to get at the emulator debugging i/f, maybe that's not available on the web version.) See  Matt Godbolt on Robot Semantic Models of CPUs  and  RP2040 - 6502 Emulator - TIM, Tiny Basic, and EHBasic . Subscribe to Computerphile .

I think he's quite wrong about a lot of things. Aristotle used mathematics constantly, as a way to unify human thought itself. See  Neil Turok Also Going into The Sci-fi Movie Busines  and  Norman Wildberger on Representing Negative Numbers as M-sets . See also  Another Introduction to Geometric Algebra . Subscribe to  Insights into Mathematics .

We need to be able to do this stuff without real numbers, and with a well-defined programming language which elucidates rather than obscures the underlying mathematics. See  Norman Wildberger on The End of The World ,  Learning Standard ML ,  Geometric Algebra  and  Soviet Mathematics . See resources here:  https://bivector.net/tools.html Subscribe to Bivector .

See Series on Soviet and East European Mathematics : Volume 1 p-Adic Analysis and Mathematical Physics  and  Number Theory as The Ultimate Physical Theory (CERN-TH.4781/87) . See these posts:  V.I. Arnold on Teaching Mathematics  and  Anton Petrov - Mindblowing Video of Plants Talking to Each Other In Real Time and Other Complex Life Forms .

I am having to learn this again, because I've forgotten so much of it. Here are some resources: Mads Tofte's Standard ML for Computer Scientists Programming in Standard ML ’97: A Tutorial Introduction   by Stephen Gilmore The Definition of Standard ML (Revised) , by Robin Milner, Mads Tofte, Robert Harper and David MacQueen. Commentary on Standard ML , by Robin Milner and Mads Tofte. If you want to try some simple programs in a web browser without having to install anything on your computer, see the amazing  SOSML  which is here:  https://sosml.org/ . Moscow ML is still in business:  https://mosml.org/ . The easiest way to get a half-comfortable local development environment is still GNU emacs with the SML-Mode package : type  M-x package-install RET sml-mode RET  now if only I knew how to turn off the stupid indenting minor-mode which keeps changing what I type, ... I mean, the shit it adds is not even half-right!

Go to this page: https://enkimute.github.io/ganja.js/examples/coffeeshop.html  click "New" and then paste this into the window and press "Save", then "Run". It's amazing! See  n-Dimensional rigid body dynamics in PGA . window.d = 3; Algebra(d,0,1,()=>{      var points = [...Array(2**d)]       .map((x,i)=>i.toString(2))       .map(x=>('000'+x).slice(-d))       .map(x=>x.split('').map(x=>x-0.5))       .map(x=>!(1e0 + x*[1e1,1e2,1e3,1e4]));          var edges = points.map((a,i)=>points.map((b,j)=>     (i<=j||(i^j)&((i^j-1))?0:[a,b]     ))).flat();      var attach = points[2**d-1];   var F = (M,B)=>{     var Gravity = !(~M >>> -9.81e02);     var Damping = -0.25*!B;     var Hooke = 8*(~M >>> attach) & points[2**d-1];     return Gravity + Damping + Hooke;   }      var state = [1, 1e12 + 2e13 + 1e24],       ds = (M,B)=>[-0.5*M*B,!(F(M,B)-0.5*(!B*B-B*!B))];          return this.graph(()

See this Wikipedia page:  Maneuvering Characteristics Augmentation System  for lots of gory details of the series of problems. Nebula sounds like a hive of activity:  https://go.nebula.tv/realengineering . Watch this video there:  https://nebula.tv/videos/realengineering-the-questionable-engineering-of-the-737-max Subscribe to Real Engineering .

This is a really interesting essay he wrote in 1997. See  Teaching Mathematics . On modeling, he describes a problem: The scheme of construction of a mathematical theory is exactly the same as that in any other natural science. First we consider some objects and make some observations in special cases. Then we try and find the limits of application of our observations, look for counter-examples which would prevent unjustified extension of our observations onto a too wide range of events ...  As a result we formulate the empirical discovery that we made (for example, the Fermat conjecture or Poincaré conjecture) as clearly as possible. After this there comes the difficult period of checking as to how reliable are the conclusions. At this point a special technique has been developed in mathematics. This technique, when applied to the real world, is sometimes useful, but can sometimes also lead to self-deception. This technique is called modelling. When constructing a model, the following

1:30 Volatile compounds released by plants. See  Green leaf volatile sensory calcium transduction in  Arabidopsis by Yuri Aratani, Takuya Uemura, Takuma Hagihara, Kenji Matsui & Masatsugu Toyota  and  Insect Herbivory Selects for Volatile-Mediated Plant-Plant Communication  by Aino Kalske, Kaori Shiojiri, Akane Uesugi, Yuzu Sakata, Kimberly Morrell and André Kessler . Plant volatile organic compounds (VOCs) are major vehicles of information transfer between organisms and mediate many ecological interactions . Altering VOC emission in response to herbivore damage has been hypothesized to be adaptive, as it can deter subsequent herbivores, attract natural enemies of herbivores, or transmit information about attacks between distant parts of the same plant. Neighboring plants may also respond to these VOC cues by priming their own defenses against oncoming herbivory, thereby reducing future damage ... Plants from populations that experienced selection by insect herbivory induced resis

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Rethinking Computer Graphics: Calculating Points on Curves: Drawing graphs: The video Bases of Polynomial Spaces  (see above) is #20 in this list: See  Freya Holmér on Continuity of Splines ,  David Hestenes - Tutorial on Geometric Calculus  and  Modelling Probability Distributions and Solving Differential Equations . Subscribe to Norman Wildberger . David Hetenes on Meaning in Mathematics (which is Physics, as far he is concerned) https://t.co/G0YpglyABR Then he talks about putting things together and that's where you discover the meanings. Reminds me of Henri Atlan's Uncommon Finalities. https://t.co/e80UGvmcJX — eternal Doorman (@IanANGrant66) January 19, 2024

Well I don't know, because I haven't read his book, but see  The Second Law: Resolving the Mystery of the Second Law of Thermodynamics by Stephen Wolfram .  At  24:43 I always get lost at this point in the description of physical entropy. "Entropy is: You know a certain number of things about a system, a certain amount about a system, and you say 'there are gas molecules and they're all in this box, and there are a billion of them' and that's all you know. Then the question is 'well, how many possible configurations of the system could there be that are consistent with those constraints that they have?' ... as Boltzmann originally said, it's sort of quantized, and that the gas molecules are just in some grid of possible positions, and you say 'how many possible positions are they in?' and entropy is just the exponent, of how many possible configurations there are." My problem is that all you know is how many molecules are in that

Subscribe to Hélène Vogelsinger . Subscribe to Dr Peacock . See also  Hélène Vogelsinger - M e t a p h y s i c a l A l t e r a t i o n ( 3 / 4 ) .

Subscribe to Aurora . With some targetted YouTube ads: I think we need better data. I am trying to make that possible, but I need some peace and quiet and access to information on the Internet without being bombarded by people spending money targetting fundraising ads. Some of them are very hard to bear. See  Dr. Peacock and Hélène Vogelsinger - Cognitive Dissonance (Hard Version) .

Subscribe to Lee Camp . They got the idea from The London Eye, I think. Subscribe to Academy of Ideas .

And a lot of other things:  https://hackaday.com/2021/03/03/what-uses-more-power-than-argentina-but-doesnt-dance-the-tango/ . See the shownotes and listen here:  https://hackaday.com/2024/01/12/hackaday-podcast-episode-252-x1plus-hacks-bambu-scotto-builds-a-katana-keyboard-and-bass-puts-out-fire/ . See Jade's two videos about fairness here:  Modelling Probability Distributions and Solving Differential Equations. What's important is what you know. Knowledge is the most important thing to everyone. That's what important  actually means, you know. Subscribe to UpAndAtom .

This sounds like a catalog of what's wrong with modern life. After watching her last video, where she talked about wanting to go snowboarding and needing to find some way to fit that in, I thought, well, if she had been going to a conference in Aspen or Davos or somewhere like that then she would be able to do things like that easily, ...  Then it snowed and I went for a walk the next day. I sat by a favorite tree and noticed there was still some snow on the ground. So I ate a tiny but of the snow from a fallen leaf and it tasted great, and I thought "Well, that's my snowboarding trip this year. Get on with doing some more work". I used to like going to the Pyrenees, and it is especially good in winter, but that part of my life is over now. It was good when it happened and I value that immensely, but now it's passed. To live like that you need ridiculous amounts of money and you have to spend most of your time earning that money and you have no time to think about

See  Spread Polynomials : 27:48 On factorization of spread-polynomials, see  Lewis Carroll - Crocodile Story Subscribe to Norman Wildberger . JPL Orbits & Ephemerides: https://ssd.jpl.nasa.gov/orbits.html See also this very impressive student project, which is a digital orrery that uses the JPL Ephemerides: https://www.robots.ox.ac.uk/~mjc/Papers/3YP_Report.pdf  This seems to be the basis for a way to make a space-flight simulator for planets. See  Trying to Make a Sci-Fi Movie  for the context. See also  Laplace Transform : Algebraic construction The Laplace transform can be alternatively defined in a purely algebraic manner by applying a field of fractions construction to the convolution ring of functions on the positive half-line. The resulting space of abstract operators is exactly equivalent to Laplace space, but in this construction the forward and reverse transforms never need to be explicitly defined (avoiding the related difficulties with proving convergence).  Mikusiński