The size of isoperimetric surfaces in 3-manifolds and a rigidity result for the upper hemisphere
arXiv:0706.3483
Abstract
We characterize the standard as the closed Ricci-positive 3-manifold with scalar curvature at least 6 having isoperimetric surfaces of largest area: . As a corollary we answer in the affirmative an interesting special case of a conjecture of Min-Oo's on the scalar curvature rigidity of the upper hemisphere..
9 pages. Thoroughly revised final version. Comments welcome!