### Neumann and Mixed Problems on Curvilinear Polyhedra

*Monique Dauge*

We prove regularity results in L^{p} Sobolev
spaces. On one hand, we state
some abstract results by L^{p} functional
techniques: Exponentially decreasing
estimates in dyadic partitions of cones and dihedra, operator valued
symbols and
Marcinkievicz's theorem. On the other hand, we derive more concrete
statements
with the help of estimates about the first non-zero eigenvalue of some
Laplace-Beltrami operators on spherical domains.

*Integral Equations Oper. Theory. * **15**, 227--261, 1992.