By applying the unit normal flow to well-known inequalities in hyperbolic space
and in the
sphere
,
we derive some new inequalities of Alexandrov–Fenchel type for closed convex
hypersurfaces in these spaces. We also use the inverse mean curvature flow in the
sphere to prove an optimal Sobolev-type inequality for closed convex hypersurfaces in
the sphere.
Keywords
isoperimetric inequality, convex hypersurface,
Alexandrov–Fenchel-type inequality, $k$-th order mean
curvature, Gauss–Bonnet curvature