## Ninth Linkfest

Welcome to the Ninth Linkfest. This time around, I am experimenting with splitting the “Technical” links up into two parts: “Technical But Followable”, and “Technical (Harder to Follow)”. This is of course, pretty subjective. Due to my own focus, stuff about logic is obviously easier for me to follow, while stuff about (say) Lie groups is harder for me to follow and hence more likely to end up in the latter grouping. But hopefully my bias shouldn’t be *too* different from most peoples’. After all, it’s an undisputed fact that mathematical logic is the most beautiful field of math

The previous linkfest is here: Eighth Linkfest

## Technical (But Followable)

Scott Aaronson: What Alan Turing did for his PhD

Michael O’Connor: A Logical Interpretation of some bits of Topology

Emmanuel Kowalski: Cartain’s “Sur certains cycles arithmétiques”

Tom Leinster: Hadwiger’s Theorem

Richard Lipton: NP-Intermediate?

The Physicist: What does a measurement in quantum mechanics do?

K.W. Regan: Name That Graph, Triple Century Post (or: How does continuous math impact discrete complexity?)

Terence Tao: Polynomial bounds via nonstandard analysis, On the number of solutions to 4/p=1/n_{1}+1/n_{2}+1/n_{3}

## Technical (Harder to Follow)

John Armstrong: Distributions, Integral Submanifolds, The Hopf Fibration, Tensor Bundles

John Bamberg: New locally 9-arc-transitive graphs!

Julien Cassaigne, James D. Currie, Luke Schaeffer, and Jeffrey Shallit: Avoiding Three Consecutive Blocks of the Same Size and Same Sum (arXiv)

Tanya Khovanova: Complexity of Periodic Strings

Steven Sam: Do the rank k matrices form an affine variety?

Sigfpe: An elementary way to approach Fourier transforms

David Speyer: Why graded bi-algebras have antipodes

Terence Tao: Two small facts about Lie groups

Qiaochu Yuan: The Representation Theory of SU(2)

## Non-Technical

Gavin Andreson: Bitcoins worth more than the computer they are stored on

Avoision: The clock in the mountains

Diana Barnes-Brown: TJ Maxx flunks old school

Michel Bauwens: The Alliance to Develop Power in western Massachusetts, The emergence of a movement against corporate personhood

Blogstrapping: An Open Letter To Barnes & Noble About Text Files

BlueShoe: Let’s Enjoy Japanese: “Before You Know It”

Jelle Bruinsma: The Battle for Syntagma

CTK: What is it about math language that makes it confusing?

Delta: On Tau (on the movement to replace pi with 2*pi)

James Feudo: Will Facebook still be around in five years?

Lance Fortnow: Quantum TiVo

Michael Frank: We the Processors (or: on using Bitcoin algorithms to run elections)

The Futurist: The End of Petrotyranny

Bradley Garrett: An open letter to the British Transport Police

Andrew Gelman: Different goals, different looks: Infovis and the Chris Rock effect

Simon Grey: I was right (about criminals disguising as police), Happiness, A reasonable proposal (to raise or eliminate speed limits)

Rhys Jones: A new approach to printing metals

Khatzumoto: Top 10 Great Japanese Movies from 1998 to 2008

Cap Khoury: Happy Tau Day 2011!, Tau Day Leftovers

Orchid64: Won’t Miss #335: kisoku wa kisoku da (“Rules are Rules”)

Melanie Laffin: “The Pigeonhole Principle” (or: On Academic Over-Specialization)

Alex Papadimoulis: Trans-Atlantic Time Trap, Supported Image Formats, The Dreaded Zebra, and The Un-Fix

Sudip Paul: My First Teaching Experience

Remy Porter: The Key to a Good Schema (or: yet another database horror story)

Sam Shah: Taught Curriculum vs. Learned Curriculum

Peter Smith: Thank Heavens that’s over… (a retiring philosopher’s thoughts while clearing out his desk)

SonicCharmer: The “Cars” Franchise is This Generation’s Star Wars, I am not DSK, Against (Movie) Remakes

Ben Webster: Is having a pay copy-editing service a new low for Elsevier?

Peter Woit: Higher Speculations (a look back at “vortex theory”, the 19th century equivalent of string theory)

## Art, Photography, etc.

Avoision: Crazy Hail Storm in Logan Square

Telefunker: Magran (an abandoned grain mill in Belgium), Fort Steendorp (Belgium)

Freddie Wong: Man vs. Katamari (YouTube)

Nick Yates: Buffalo!