Green Operators in the Edge Calculus
  The task to construct parametrices of elliptic differential operators on a manifold with edges requires a calculus of operators with a two-component principal symbolic hierarchy, consisting of (edge-degenerate) interior and (operator-valued) edge symbols. This so-called edge-algebra can be interpreted as a generalisation of the (pseudo-differential) algebra of boundary value problems without the transmission property at the boundary. We study new properties of the edge-algebra, in particular, what concerns the role of Green operators and their kernel representations. 
B.-W. Schulze and A. Volpato