History of Subring

	Revision 2 . . December 16, 2001 2:08 pm by AxelBoldt
	Revision 1 . . July 30, 2001 6:59 am by Buzco

---

Difference (from prior major revision) (no other diffs)

Changed: 1c1,4

#redirect SubRing

Given a ring (R, +, *), we say that a subset S of R is a subring thereof if it is a ring under the restriction of + and * thereto, and contains the same unity as R. A subring is just a subgroup of (R, +) which contains 1 and is closed under multiplication. Every ring has a unique smallest subring, isomorphic to either the integers Z or some modular arithmetic Zn.