Publications, Research Papers, and Lectures
Here is information are my various research papers, lecture handouts, textbooks, and so on.
Major Writings
My two largest projects at the moment are

My textbook Euclidean Geometry in Mathematical Olympiads. 300 pages, accepted for publication by MAA Problem Book Series. You can purchase the ebook here. Information on hard copies forthcoming.

My personal exposition project An Infinitely Large Napkin.
About 600 pages. See here for a listing of download links.
Please see the links above for more information.
Research Publications

The 26 Wilfequivalence classes of length five quasiconsecutive patterns
E. Chen, S. Narayanam. Submitted for publication. 
Avoiding algebraic integers of bounded house in orbits of rational functions over cyclotomic closures
E. Chen. In preparation. 
Linear polychromatic colorings of hypercube faces
E. Chen. Submitted for publication. 
Linnik's Theorem on SatoTate Laws on elliptic curves with complex multiplication
E. Chen, P. Park, and A. Swaminathan. Published in Research in Number Theory. 
Elliptic curve variants of the least quadratic nonresidue problem and Linnik's Theorem
E. Chen, P. Park, and A. Swaminathan, submitted for publication. 
On Logarithmically Benford Sequences
E. Chen, P. Park, and A. Swaminathan. Published in Proceedings of the AMS.
Lectures
Here are lecture notes for lectures, sessions, etc. that I have given, generally to high school students. These are in general easier than my Olympiad handouts. They also tend to leave out lots of details (after all, the handout usually accompanies a twohour talk).
To compile these documents in LaTeX, you will need evan.sty.
Berkeley Math Circle  Advanced Group

Barycentric Coordinates (pdf) (tex)
A quick introduction to barycentric coordinates. 
Combinatorial Nullstellensatz (pdf) (tex)
Applies the combinatorial nullstellensatz to several olympiadstyle problems.
Berkeley Math Circle  Intermediate and Intermediate II Group

Triangle Centers (pdf) (tex)
Standard fare on the Euler line and the ninepoint circle. Might be interesting to people starting out on olympiad geometry. 
Set Theory (pdf) (tex)
Talked about ZFC and the construction of the ordinals. Essentially equivalent to [this blog post of mine][ordinals]. 
Parallelograms (pdf) (tex)
All you have to do is construct a parallelogram! 
BAMO Preparation (pdf) (tex)
A combinatorially flavored practice session for the Bay Area Math Olympiad.
Miscellaneous
 Combinatorial Nullstellensatz (SPARC) (pdf) (tex)
Slides from an informal lecture I gave on the nullstellensatz at SPARC 2013.