data.set
========

Subsets of an arbitrary type.

* [basic](basic.lean) : unions, intersections, etc.
* [comm_semiring](comm_semiring.lean)
* [function](function.lean) : functions from one set to another
* [map](map.lean) : set functions bundled with their domain and codomain
* [finite](finite.lean) : the "finite" predicate on sets
* [card](card.lean) : cardinality (for finite sets)
* [filter](filter.lean) : filters on sets
* [classical_inverse](classical_inverse.lean) : inverse functions, defined classically
* [equinumerosity](equinumerosity.lean)