4.Set - Mathematics
A set is a collection of distinct, unordered objects. Sets are typically collections of numbers, though a set may contain any type of data (including other sets)
-- http://math.wikia.com/wiki/Set
9.Mathematics - Davis Wiki
A Mathematics ArXiv front and the Journal of Mathematical Physics are also run from ... In fact, any element in a group acts as a permutation of that group's elements. ...
-- http://daviswiki.org/Mathematics