Support of a Weil divisor
= Support of a Weil divisor
{title2=$\operatorname{Supp}(D)=\bigcup_{a_P\ne0}P$}
For $D=\sum_P a_PP$, its support is the union of the prime divisors $P$ with $a_P\ne0$. Negative as well as positive coefficients contribute. A point outside the support has a neighbourhood on which the divisor is zero.