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Most cited
Posts that commenters keep linking to, ranked by how many different people have cited them in Hacker News comments. 417 posts.
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Meditations on Moloch (2014)
I. Allen Ginsberg’s famous poem on Moloch:What sphinx of cement and aluminum bashed open their skulls and ate up their brains and imagination? Moloch! Solitude! Filth! Ugliness! Ashcans and u…
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Regular expression matching can be simple and fast (2007)
This is a tale of two approaches to regular expression matching. One of them is in widespread use in the standard interpreters for many languages, including Perl. The other is used only in a few places, notably most implementations of awk and grep. The two approaches have wildly different performance characteristics:
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Solving Every Sudoku Puzzle (2006)
Every square has exactly 3 units and 20 peers. For example, here are the units and peers for the square C2 :
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Category Theory for Programmers (2014)
Table of Contents Part One Category: The Essence of Composition Types and Functions Categories Great and Small Kleisli Categories Products and Coproducts Simple Algebraic Data Types Functors Functo…
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How Not To Sort By Average Rating
Users are rating items on your website. How do you know what the highest-rated items are?
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The control group is out of control (2014)
I. Allan Crossman calls parapsychology the control group for science. That is, in let’s say a drug testing experiment, you give some people the drug and they recover. That doesn’t tell …
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Quantum mechanics as a generalization of probability (2007)
There are two ways to teach quantum mechanics. The first way -- which for most physicists today is still the only way -- follows the historical order in which the ideas were discovered. So, you start with classical mechanics and electrodynamics, solving lots of grueling differential equations at every step. Then you…
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Bayes' Theorem explained by Yudkowsky
Bayes’ Theorem for the curious and bewildered; an excruciatingly gentle introduction.
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Who Can Name the Bigger Number?
[This essay in Spanish] [This essay in French] [This essay in Chinese] In an old joke, two noblemen vie to name the bigger number. The first, after ruminating for hours, triumphantly announces "Eighty-three!" The second, mightily impressed, replies "You win." A biggest number contest is clearly pointless when the…
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The Categories Were Made for Man, Not Man for the Categories (2014)
I. “Silliest internet atheist argument” is a hotly contested title, but I have a special place in my heart for the people who occasionally try to prove Biblical fallibility by pointing …
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Implementing Regular Expressions
This page collects resources about implementing regular expression search efficiently.
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A Primer on Bézier Curves
A detailed explanation of Bézier curves, and how to do the many things that we commonly want to do with them.
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Ask HN: How do you solve hard problems if you can't make incremental progress?
Ron Jeffries attempts to create a sudoku solver - here , here , here , here and here . (You really ought to read these articles. They are u...
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Exponential Economist Meets Finite Physicist (2012)
[ An updated treatment of some of this material appears in Chapter 2 of the Energy and Human Ambitions on a Finite Planet (free) textbook, also mirrors a 2022 article in Nature Physics . . ]
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A collection of things that are Turing-complete by accident (2013)
A list of things that were not supposed to be Turing-complete, but are.
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There's more to mathematics than rigour and proofs (2007)
The history of every major galactic civilization tends to pass through three distinct and recognizable phases, those of Survival, Inquiry and Sophistication, otherwise known as the How, Why, and Wh…
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How to Fold a Julia Fractal
A tale of numbers that like to turn: a different look at complex numbers and the strange things they do.
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What if You Only Invested at Market Peaks?
What happens when you only invest at the peaks of the market by being the world's worst market timer.
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A trip through the Graphics Pipeline
Welcome. This is the index page for a series of blog posts I’m currently writing about the D3D/OpenGL graphics pipelines as actually implemented by GPUs. A lot of this is well known among gra…
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Does one have to be a genius to do maths?
Better beware of notions like genius and inspiration; they are a sort of magic wand and should be used sparingly by anybody who wants to see things clearly. (José Ortega y Gasset, “Notes on t…
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Stephen Wolfram, A New Kind of Science
Attention conservation notice : Once, I was one of the authors of a paper on cellular automata . Lawyers for Wolfram Research Inc. threatened to sue me, my co-authors and our employer, because one of our citations referred to a certain mathematical proof, and they claimed the existence of this proof was a trade secret…
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GPS and Relativity
People often ask me "What good is Relativity?" It is a commonplace to think of Relativity as an abstract and highly arcane mathematical theory that has no consequences for everyday life. This is in fact far from the truth.
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Entropy Attacks
The conventional wisdom is that hashing more entropy sources can't hurt: if H is any modern cryptographic hash function then H(x,y,z) is at least as good a random number as H(x,y), no matter how awful z is. So we pile one source on top of another, hashing them all together and hoping that at least one of them is good.
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Are You Living In a Computer Simulation? (2003)
The original paper that introduced the simulation argument
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How a Kalman filter works, in pictures
I have to tell you about the Kalman filter, because what it does is pretty damn amazing.
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Medical researcher discovers integration, gets 75 citations
(Note: this post is `just for fun;’ no premeds, doctors, researchers, or nobel laureates were meant to be offended in the writing of this post.) The bane of many American physics grad student…