Characteristic (algebra) – Wikipedia, the free encyclopedia

In mathematics, the characteristic of a ring R, often denoted char(R), is defined to be the smallest number of times one must use the ring\’s multiplicative identity element (1) in a sum to get the additive identity element (0); the ring is said to have characteristic zero if this sum never reaches the additive identity.

That is, char(R) is the smallest positive number n such that

underbrace{1+cdots+1}_{n text{ summands}} = 0

if such a number n exists, and 0 otherwise.

via Characteristic (algebra) – Wikipedia, the free encyclopedia.