About the Connes Embedding Conjecture---Algebraic approaches---
arXiv:1212.1700
Abstract
This is an expanded lecture note for "Masterclass on sofic groups and applications to operator algebras" (University of Copenhagen, 5-9 November 2012). It is about algebraic aspects of the Connes Embedding Conjecture. It contains new proofs of equivalence of the Connes Embedding Conjecture, Positivstellensatze for trace positive polynomials, Kirchberg's Conjecture, and Tsirelson's Problem.
32 pages; The title is changed and the contents is expanded for publication (v2); Minor changes (v3)