Let $R$ be a ring. The characteristic of $R$, written $\chara R$, is the smallest $n\in\N^+$ such that
\[n\cdot 1 = 0,\]if it exists; otherwise, we let $\chara R=0$.
Let $R$ be a ring. The characteristic of $R$, written $\chara R$, is the smallest $n\in\N^+$ such that
\[n\cdot 1 = 0,\]if it exists; otherwise, we let $\chara R=0$.