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Mathematics Low‑priority 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 Low This article has been rated as Low-priority on the project's priority scale.

This article is pretty unclear which version of concordance is meant: smooth? locally flat? Any disks?Dylan Thurston (talk) 05:34, 18 November 2014 (UTC)[reply]