A split special Lagrangian calibration associated with frame vorticity

MARCOS SALVAI

Advances in Calculus of Variations

Walter de Gruyter GmbH

Año: 2023

1864-8258

Let M be an oriented three dimensional Riemannian manifold. We define a notion of vorticity of local sections of the bundle SO(M) --> M of all its positively oriented orthonormal tangent frames. When M is a space form, we relate the concept to a suitable invariant split pseudo-Riemannian metric on Iso_o (M) cong SO(M): A local section has positive vorticity if and only if it determines a space-like submanifold. In the Euclidean case we find explicit homologically volume maximizing sections using a split special Lagrangian calibration. We introduce the concept of optimal vorticity and give an optimal screwed global section for the three-sphere. We prove that it is also homologically volume maximizing (now using a common one-pointsplit calibration). Besides, we show that no optimal section can exist in the Euclidean and hyperbolic cases.