Height of minimal surfaces: sharp thresholds

Abstract: The confinement theorem of [CM1] gives Euclidean volume growth for a proper minimal submanifold whose height over a plane is sublinear. Such volume growth places strong restrictions on the geometry. This leaves linear height as the natural borderline and raises the question of which, if any, linearly growing cones still force Euclidean growth. Here we determine this borderline sharply for proper holomorphic curves in $C^2$. There are two sharp thresholds for the aperture depending on the Kähler angle $θ$ of the two-plane $Π$: $\tan(θ/2)$ and $\cot(θ/2)$. No proper holomorphic curve exists below the first, every such curve is algebraic below the second, and superquadratic proper holomorphic disks exist above the second. These conclusions extend to holomorphic submanifolds of arbitrary dimension and codimension. For stationary integral varifolds there are again three regimes: sublinear height forces Euclidean growth, narrow cones of aperture $\varepsilon$ force polynomial growth with exponent $n+O(\varepsilon^2)$, and wide cones allow arbitrarily fast growth. The order $\varepsilon^2$ is sharp: already in $R^3$, for every small $\varepsilon>0$ there are examples in a cone of aperture $\varepsilon$ whose volume grows at least like $r^{2+\frac45\varepsilon^2}$.