On traces for functional spaces related to Maxwell's equations Part II: Hodge decompositions on the boundary of Lipschitz polyhedra and applications

Hodge decompositions of tangential vector fields defined on piecewise regular manifolds are provided. The first step is the study of L2 tangential fields and then the attention is focused on some particular Sobolev spaces of order -1/2. In order to reach this goal, it is required to properly define the first order differential operators and to investigate their properties. When the manifold F is the boundary of a polyhedron Q, these spaces are important in the analysis of tangential trace mappings for vector fields in H(curl, fi) on the whole boundary or on a part of it. By means of these Hodge decompositions, one can then provide a complete characterization of these trace mappings: general extension theorems, from the boundary, or from a part of it, to the inside; definition of suitable dualities and validity of integration by parts formulae.