Dimension drop by a non-zero-divisor
= Dimension drop by a non-zero-divisor
If $x$ is a non-zero-divisor in a finite-dimensional Noetherian ring $A$, then
$$
\dim(A/(x))\leq\dim A-1.
$$
Every prime chain above $(x)$ can be extended downward by a minimal prime of $A$, because a non-zero-divisor belongs to no minimal prime.