Uniqueness results for free-boundary minimal hypersurfaces in conformally Euclidean balls and annular domains

In this paper we prove that a flat free-boundary minimal $n$-disk, $n\ge 3$, in the unit Euclidean ball $B^{n+1}$ is the unique compact free boundary minimal hypersurface in the unit Euclidean ball which the squared norm of the second fundamental form is less than either $\frac{n^2}{4}$ or $\frac{(n-2{)}^2}{4\mathrm{\mid }x{\mathrm{\mid }}^2}$. Moreover, we prove analogous results for compact free boundary minimal hypersurfaces in annular domains with a conformally Euclidean metric.