Roofs and Convexity
  Convex roof extensions are widely used to create entanglement measures in quantum information theory. The aim of the article is to present some tools which could be helpful for their treatment. Sections 2 and 3 introduce into the subject. It follows descriptions of Wootter's method, of the "subtraction procedure", and examples on how to use symmetries. 
Armin Uhlmann
quant-ph math-ph math.MP