Let $I=\langle a_1,\dots, a_s\rangle, J=\langle b_1,\dots, b_t\rangle$ be ideals of arbitrary commutative ring.
Then we know that $I+J=\langle a_1,\dots, a_s, b_1,\dots, b_t\rangle, IJ=\langle\{a_ib_j \mid 1 \leq i \leq s, 1\leq j \leq t\}\rangle$.
Also $IJ\subseteq I\cap J \subseteq I+J$.
I wonder about the generators of $I\cap J$. Is it possible that know the generators? Or is it finitely generated?