On a Liu--Yau type inequality for surfaces

Abstract

Let $\Omega$ be a compact and mean-convex domain with smooth boundary $\Sigma :=\partial \Omega$, in an initial data set $(M^3,g,K)$, which has no apparent horizon in its interior. If $\Sigma$ is spacelike in a spacetime $(\E^4,g\_\E)$ with spacelike mean curvature vector $\mathcal{H}$ such that $\Sigma$ admits an isometric and isospin immersion into ${\mathbb{R}}^3$ with mean curvature $H\_0$, then: \begin{eqnarray*} \int\_Σ|\mathcal{H}|dΣ\leq\int\_Σ\frac{H\_0^2}{|\mathcal{H}|}dΣ. \end{eqnarray*} If equality occurs, we prove that there exists a local isometric immersion of $\Omega$ in ${\mathbb{R}}^{3,1}$ (the Minkowski spacetime) with second fundamental form given by $K$. In Theorem liu-yau-minkowski, we also examine, under weaker conditions, the case where the spacetime is the $(n+2)$-dimensional Minkowski space ${\mathbb{R}}^{n+1,1}$ and establish a stronger rigidity result.

References in corpus (2)

• Isometric embeddings into the Minkowski space and new quasi-local mass
• A holographic principle for the existence of parallel spinor fields and an inequality of Shi-Tam type