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