Definition
Let $A$ be a commutative ring with unity.
Let $I \subseteq A$ be an ideal.
The annihilator of $I$ is the ideal consisting of the elements $a \in A$ such that:
- $\forall x \in I: a \cdot x = 0$
where $0 \in A$ is its zero.
Also see
- Results about annihilators can be found here.