This article is rated Start-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects:

Mathematics This article is within the scope of WikiProject Mathematics, a collaborative effort to improve the coverage of mathematics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.MathematicsWikipedia:WikiProject MathematicsTemplate:WikiProject Mathematicsmathematics articles ??? This article has not yet received a rating on the project's priority scale.

The second example is wrong: the triangle inequality doesn't follow. Some kind-of-convexity property is missing. — Preceding unsigned comment added by 139.82.27.31 ( talk) 21:45, 17 March 2011 (UTC) reply