A Counterexample for a Conjecture about the Catenarity of Polynomial Rings

This paper solves a long-standing open question: it is known that, if R is a Noetherian ring such that R[X] is catenarian, then so is R[X, Y], and, hence, R is universally catenarian; yet the non-Noetherian case remains unsolved. We do provide here an answer with a two-dimensional coequidimensional counterexample.