We investigate the
isoperimetric problem of finding the regions of prescribed volume with minimal
boundary area between two parallel horospheres in hyperbolic 3-space (the part of
the boundary contained in the horospheres is not included). We reduce the problem
to the study of rotationally invariant regions and obtain the possible isoperimetric
solutions by studying the behavior of the profile curves of the rotational surfaces with
constant mean curvature in hyperbolic 3-space. We also classify all the connected
compact rotational surfaces M of constant mean curvature that are contained in the
region between two horospheres, have boundary ∂M either empty or lying
on the horospheres, and meet the horospheres perpendicularly along their
boundary.
Keywords
constant mean curvature surfaces, hyperbolic space,
isoperimetric problem
Instituto de Matemática, Estatística
e Computação Científica
Universidade Estadual de Campinas
Praça Sérgio Buarque de Holanda, 651
13083-859 Campinas - SP
Brazil