Solution
= Solution
The <Chinese remainder theorem> identifies
$$
R/I\cong\prod_iR/(p_i^{e_i}).
$$
\b[Thus a class is a unit exactly when its image modulo every $p_i$ is nonzero, equivalently when no $p_i$ divides a representative.]
= Solution
The <Chinese remainder theorem> identifies
$$
R/I\cong\prod_iR/(p_i^{e_i}).
$$
\b[Thus a class is a unit exactly when its image modulo every $p_i$ is nonzero, equivalently when no $p_i$ divides a representative.]