The Dedekind-domain containment conjecture for idempotent plethories

Let $D$ be a Dedekind domain of characteristic zero with quotient field $K$. The Dedekind-domain containment conjecture. Every idempotent $D$-plethory is contained in $K[e]$, or, equivalently, ${\operatorname{Int}}(D)$ is the largest idempotent $D$-plethory and is therefore the epimorphic hull of the trivial $D$-plethory. This conjecture addresses the classification of idempotent plethories and the existence of an epimorphic hull of the trivial plethory for Dedekind domains.