Radical classes of distributive lattices having the least element

summary:Let $\mathcal D$ be the system of all distributive lattices and let $\mathcal D_0$ be the system of all $L\in \mathcal D$ such that $L$ possesses the least element. Further, let $\mathcal D_1$ be the system of all infinitely distributive lattices belonging to $\mathcal D_0$. In the present paper we investigate the radical classes of the systems $\mathcal D$, $\mathcal D_0$ and $\mathcal D_1$