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Entropy 2010, 12(7), 1799-1832; doi:10.3390/e12071799
Roofs and Convexity
Received: 5 June 2010; in revised form: 5 July 2010 / Accepted: 9 July 2010 / Published: 20 July 2010
(This article belongs to the Special Issue Quantum Information)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: 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 the Wootters' method, of the "subtraction procedure", and examples on how to use symmetries.
Keywords: roofs; convex roof extensions; entanglement measures