On the inverse mean curvature flow by parallel hypersur-
faces in space forms
Space forms; Parallel hypersurfaces; Inverse mean curvature
flow; Isoparametric hypersurfaces.
We prove that an oriented hypersurface in a space form, whose mean cur-
vature does not vanish at any point, is an initial condition for a solution
to the inverse mean curvature flow (IMCF) by parallel hypersurfaces if and
only if it is isoparametric. Considering the isoparametric hypersurfaces in
space forms, we obtain the solutions to the IMCF by parallel hypersurfa-
ces explicitly. Moreover, we study these solutions in detail, describing their
behavior in the maximal interval where they are defined. For the isopara-
metric hypersurfaces in the hyperbolic space and in the sphere, with two
or four distinct principal curvatures, we consider the additional assumption
that these curvatures have the same multiplicity.