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Math & Algorithms
The most popular blog posts about math & algorithms on Hacker News. 50 posts.
How Credit Card Numbers Are Generated
Visa,Master Card,Discover, and American Express credit card validation and generation techniques using the luhn algorithm.
Visualizing the Fourth Dimension Using Color
Color can be used to indicate position in 4D space
The odd one out - inspired by IQ tests
Mathematics, applications of mathematics to life in general, and my life as a mathematician.
The Shocking State of Contemporary "Mathematics"
I just came back from attending the 1052nd AMS (sectional) meeting at Penn State, last weekend, and realized that the Kingdom of Mathematics is dead. Instead we have a disjoint union of narrow specialties , and people who know everything about nothing, and nothing about anything (except their very narrow acre). Not…
A Calculus Analogy: Integrals as Multiplication
Integrals are often described as finding the area under a curve. This description is too narrow: it's like saying multiplication exists to find the area of…
A 3700-year-old proof that the diagonal of a unit square has length √2
Clicking on an image will bring up the same image at higher resolution (a download of about about 100 KB). Clicking on that in turn will download an image of about 300 KB.
Regular Expression Matching: the Virtual Machine Approach
Name the most widely used bytecode interpreter or virtual machine. Sun's JVM? Adobe's Flash? .NET and Mono? Perl? Python? PHP? These are all certainly popular, but there's one more widely used than all those combined. That bytecode interpreter is Henry Spencer's regular expression library and its many descendants.
Why the secret to speedier highways might be closing some roads: the Braess paradox
"All will be well if you use your mind for your decisions, and mind only your decisions." Help me make more videos and posts! A monthly membership directly supports the channel and allows me to make more videos that inspire students and teachers around the world. You also get early access to new videos. Support with a…
Automatic Differentiation: The most underused tool in the machine learning toolbox?
Update: (November 2015) In the almost seven years since writing this, there has been an explosion of great tools for automatic differentiation and a corresponding upsurge in its use. Thus, happily,…
Peter Selinger: MD5 Collision Demo
C:\TEMP> md5sum hello.exe cdc47d670159eef60916ca03a9d4a007 C:\TEMP> .\hello.exe Hello, world! (press enter to quit) C:\TEMP>
P.S.: The Best of Intentions
Operations in Lisp, Scheme, and other dynamically-typed languages typically dispatch on representational type information rather than intentional type information. Several broad classes of bugs and confusions can be traced to improper attempts to recover intentional type information from representation types.
The Three Projections of Doctor Futamura
Introduction The Three Projections of Futamura are a sequence of applications of a programming technique called 'partial evaluation' or 'sp...
PHYS771 Quantum Computing Since Democritus
University of Waterloo, Fall 2006 Tuesdays and Thursdays, 1:00-2:30pm BFG Building, 2nd floor seminar room (BFG2125)