Lindström–Gessel–Viennot lemma

introduction

• in physics, fermion integral formula

• Determinants, Paths, and Plane Partitions http://people.brandeis.edu/~gessel/homepage/papers/pp.pdf

• http://qchu.wordpress.com/2009/11/17/the-lindstrom-gessel-viennot-lemma/
• http://en.wikipedia.org/wiki/Lindstr%C3%B6m%E2%80%93Gessel%E2%80%93Viennot_lemma

http://math.arizona.edu/~caseyw/LGVmaster.pdf

Condensed Matter http://www.andrew.cmu.edu/user/bsauerwi/condensed.htm

application to hexagonal tiling

http://www.scribd.com/doc/62973687/17/The-Gessel-Viennot-Lemma 40p