In coarse geometry, a coarse structure on a set is a subset (of the power set of the Cartesian product of with itself) that contains the diagonal of and is closed under finite unions, subsets, relational compositions, and relational inverses. (Here composition is given by the fiber product over , whereas inverses are obtained by permuting the two factors of .)
The elements of are called entourages or controlled subsets.
Last revised on July 18, 2016 at 00:07:41. See the history of this page for a list of all contributions to it.