Order filtrations of the edge algebra (Q496821)

For a class of manifolds \(M\) with edge \(Y\) the last author introduced the edge calculus. This calculus is useful for boundary problems of (pseudo-)differential operators \(A\) which degenerate at the edge. In addition to the interior symbol \(\sigma_0(A)\) defined on \(T^*(M\setminus Y)\), there is an operator valued symbol defined on \(T^* Y\), the twisted homogeneous symbol \(\sigma_1(A)\). Using a redefinition of edge amplitude functions, the authors derive a new characterisation of the filtration of edge operators by \((\sigma_0,\sigma_1)\), simplifying earlier results.