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meiji163

169 karma · joined October 22, 2020

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meiji163··on Proof you can do hard things
A better description is "simple", not "easy".

"If you do not believe that mathematics is simple, it is only because you do not realize how complicated life is." -von Neumann

meiji163··on Ask HN: Which books do you consider real gems in your field of work/study?
Some favorite math books

Intro to Smooth Manifolds, Lee -- sweeping intro to geometry with minimal prereqs, great at balancing the nitty gritty details with conveying intuition

A Course In Arithmetic, Serre -- classically terse and elegant intro to algebraic and analytic number theory. Goes from quadratic forms to Dirichlet's theorem to modular forms in a mere 100 pgs!

Princeton Lectures in Analysis, Stein & Shakarchi -- 4 books covering much of classical/modern analysis, they really shine in their discussion of applications

The large scale structure of space-time, Hawking & Ellis -- The most mathematically satisfying treatment of general relativity I've found. High points include proof of singularity theorems!

Spin Geometry, Lawson & Michelson -- Deep dive into the enigmatic "spin groups" and their applications in geometry. Also the only good (book) reference I could find on the index theorem

meiji163··on Ask HN: Which books do you consider real gems in your field of work/study?
Milnor is a wonderful writer, in his books as well as his papers.
meiji163··on Category Theory: Lecture Notes and Online Books
> I'm not sure how useful category theory actually is in the example cases.

It's hard to say that category theory is "applied" to this or that problem. you'll hear many mathematicians call it "abstract nonsense" half-jokingly. More than anything it's a unified way of talking about mathematical structures that gives you a certain point of view (which is where it might be useful).

meiji163··on Category Theory: Lecture Notes and Online Books
The best book I've found for a non-math audience is Fong & Spivak, 7 Sketches in Compositionality.
meiji163··on A New Coefficient of Correlation
In Theorem 1.1, f is a function of random variables, which might be where you're confused.

> doesn't that mean y is a predictable function of x

Sort of: as function of real numbers, sha256 is just some deterministic function. But point is its output "looks like" a uniform random variable for any reasonable input distribution i.e. as a function of random variables the input and output variables should have 0 correlation

meiji163··on “Autism is a spectrum” doesn’t mean what you think (2019)
Not only is the diagnostic framework a joke, it's the basis of immense amounts of iatrogenic harm [0]

[0] "Anatomy of An Epidemic", Robert Whittaker

meiji163··on Ask HN: What's the best book you read in 2021?
+1 I recently read a The Idiot as well, another incredible work of his.
meiji163··on DeepMind’s new AI with a memory outperforms algorithms 25 times its size
I'd be interested to see if these models are robust against algorithms like TextFooler [0]. I'm skeptical this trend of 10x'ing the parameters will solve the "clever hans" problem.

[0]: https://github.com/jind11/TextFooler

meiji163··on The Great Offline
This article is a great example of what I'd call "mindless problematization" From what I've seen, this is you're trained to do in modern humanities departments. Take any seemingly obvious claim and "problematize" it.

It's telling that they do not say "nuance" it, rather it has to be made a _problem_. e.g. if you think "wilderness" is a thing you subscribe to a racist idea for "white male elites", if you think social media is affecting childhood development you're just caught up in the religious fervor of "scientized version of the biblical story of the Fall".

A whole lot of BS gets written this way, because these arguments have the superficial air of being subversive and contrarian.

meiji163··on AI is discovering patterns in pure mathematics that have never been seen before
I'm a fan of deepmind and all, but this story has been way overblown based on what I saw in the actual code. There's nothing particularly new about mathematicians using computers to investigate and make conjectures, even if you add ML into it.
meiji163··on Missouri found mask mandates work, but didn’t make findings public
What is the bottom line on masks and COVID-19? I am really out of the loop, since the toxicity of the debate was exhausting. The last I heard was that transmission is mostly via aerosolized viral particles, so most masks are essentially useless except N95 or higher grade.

Anyone have resources I can check out? thanks

meiji163··on Adversarial image attacks are no joke
Language models have the same defect - they are quite brittle and susceptible to black-box adversarial attacks ( eg arxiv.org/abs/1907.11932 )
meiji163··on Modern LZ Compression (2019)
I wonder if LZ would still be standard, if not for the inertia of gzip/zip? There are surely better and comparably fast algorithms (paq, ppm, etc.)
meiji163··on Music for Programming
Tim Hecker!!
meiji163··on Launch HN: Turing College (YC W21) – Online data science school
"I'm something of a scientist myself" -- Data Scientist
meiji163··on Why is AI hard and physics simple?
They'll put anything on hep-th nowadays
meiji163··on Rotations with quaternions
You can get a very good intuition with 3B1B's video ( https://www.youtube.com/watch?v=zjMuIxRvygQ )
meiji163··on Dragon Go Server
The strongest open source engine right now is KataGo (https://github.com/lightvector/KataGo)
meiji163··on LA pays $2600 per homeless tent, per month
Throwing money at a corrupt bureaucracy didn't solve a complex problem? Shocker. Proposition HHH allocated $1.2 billion towards the problem and essentially nothing was accomplished.
meiji163··on NNCP: Lossless Data Compression with Neural Networks (2019)
Using a pretrained model is a little bit cheating, you would have to include the size of the weights in the ratio
meiji163··on NNCP: Lossless Data Compression with Neural Networks (2019)
I was just working on a similar project and didn't think you could do decode without sending weights, amazing!
meiji163··on Divisible by 7 (2016)
It's just the fact that 1, 10, 100, 1000, ... = 1, 3, 2, -1, -3, -2, ... (repeating) mod 7
meiji163··on Divisible by 7 (2016)
Here's a way I do it in my head: For every block of six digits "fedcba" calculate (a-d)+3(b-e)+2(c-f). The number is divisible by 7 if the sum is divisible by 7. Fun thing is you know any number with digits "abcabc" is divisible by 7.
meiji163··on Multiplying Integers Using Fourier Transforms [pdf]
What's amusing is that multiplying integers with periodic digits is much faster using this method
meiji163··on The Fourier transform is a neural network
> What is the explanation for the flexibility in the weights? How much flexibility is there?

most of the terms are on the order of 1/N so on these would be negligible

meiji163··on The brain ‘rotates’ memories to save them from new sensations
Can someone liberate the article from behind the paywall for me?
meiji163··on Timeline of Mathematics
I have to disagree on Einstein, without the field equations it's doubtful psuedo-Riemannian geometry or so-called "Einstein manifolds" would be so big in math. There is also his work on Brownian motion and diffusion. Even if you deny he did "mathematical research" his importance for mathematics justifies him being on a timeline of mathematics .. imho
meiji163··on Lossless Text Compression [pdf]
My favorite is Context Tree Weighting (CTW) (https://ieeexplore.ieee.org/document/382012). Mathematically it's much nicer than PPM. Modern implementations of CTW achieve ratios close to or better than PPM in most domains (see e.g. P. Volf's Thesis "Weighting techniques in data compression")
meiji163··on The political case for a blanket cryptocurrency ban
>Cryptocurrency is a pseudo-asset built around the dubious notion of “speculation for speculation’s sake”

No, some people think scarcity and trustlessness make it a good store of value. This is not even addressed in the article.

> Cryptocurrencies disproportionately victimize vulnerable people and those in marginalized communities without access to traditional investments or financial advisory.

I don't see any good evidence for this, the goal of many DeFi projects is to increase access.

Overall an unfair and needlessly inflammatory evaluation. The idea that all cryptocurrency is a scam that "masses of dumb money investors" buy into is overbearingly pretentious, and a non-starter for legitimate criticism IMO.

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