Characteristic of a ring (source code)

= Characteristic of a ring
{title2=$\operatorname{char}R$}

= Ring characteristic
{synonym}

The characteristic of a <ring> $R$ is the least positive <integer> $n$ satisfying $n\cdot1_R=0$, or zero if no such <integer> exists. A nonzero <ring> of positive characteristic has prime characteristic when it is an <integral domain>.