Task:Rings and sigma-rings

This task is about the clean up of the ring of sets page and associated pages.

Task list

1. Ring of sets - clean up
2. ring generated by - clean up - move to ring of sets generated by
3. the intersection of an arbitrary family of rings is a ring - create
4. the intersection of an arbitrary family of sigma-rings is a sigma-ring - create
5. the power-set of any set is a ring of sets - create
6. the power-set of any set is a sigma-ring of sets - create