12.73 (1992)

A formation $\mathfrak{H}$ of finite groups is said to have length t if there is a chain of formations $\varnothing = \mathfrak{H}_0 \subset \mathfrak{H}_1 \subset \dots \subset \mathfrak{H}_t = \mathfrak{H}$ in which $\mathfrak{H}_{i-1}$ is a maximal subformation of $\mathfrak{H}_i$. Is the lattice of soluble formations of length $\leqslant 4$ distributive?