Druel's conjecture on the dimension of singular loci of foliations

Let $X$ be a complex projective manifold and let $d4dc$ be a foliation of dimension $k$ on $X$ with numerically trivial canonical class. If the singular locus $\operatorname{Sing}(\mathscr F)$ is non-empty, it contains a component of dimension at least $k-1$.

Druel's conjecture. The stated dimension bound holds for the singular locus of every such foliation.

This conjecture concerns the size of singular sets of foliations. The paper proves the analogous assertion under the broader condition $k\leq n/2$, without requiring projectivity or numerical triviality of the canonical class, while the full projective statement remains open in the supplied source.