@unpublished{AirapetyanWitt1997,
  author    = {Airapetyan, Ruben and Witt, Ingo},
  title     = {Isometric properties of the Hankel Transformation in weighted sobolev spaces},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-25001},
  year      = {1997},
  abstract  = {It is shown that the Hankel transformation Hsub(v) acts in a class of weighted Sobolev spaces. Especially, the isometric mapping property of Hsub(v) which holds on L²(IRsub(+),rdr) is extended to spaces of arbitrary Sobolev order. The novelty in the approach consists in using techniques developed by B.-W. Schulze and others to treat the half-line Rsub(+) as a manifold with a conical singularity at r = 0. This is achieved by pointing out a connection between the Hankel transformation and the Mellin transformation.The procedure proposed leads at the same time to a short proof of the Hankel inversion formula. An application to the existence and higher regularity of solutions, including their asymptotics, to the 1-1-dimensional edge-degenerated wave equation is given.},
  language  = {en}
}
@unpublished{HuichengWitt2002,
  author    = {Huicheng, Yin and Witt, Ingo},
  title     = {Global singularity structure of weak solutions to 3-D semilinear dispersive wave equations with discontinuous initial data},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26395},
  year      = {2002},
  language  = {en}
}
@unpublished{KapanadzeSchulzeWitt2000,
  author    = {Kapanadze, David and Schulze, Bert-Wolfgang and Witt, Ingo},
  title     = {Coordinate invariance of the cone algebra with asymptotics},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-25671},
  year      = {2000},
  abstract  = {The cone algebra with discrete asymptotics on a manifold with conical singularities is shown to be invariant under natural coordinate changes, where the symbol structure (i.e., the Fuchsian interior symbol, conormal symbols of all orders) follows a corresponding transformation rule.},
  language  = {en}
}
@unpublished{Witt2003,
  author    = {Witt, Ingo},
  title     = {Green formulae for cone differential operators},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26633},
  year      = {2003},
  abstract  = {Green formulae for elliptic cone differential operators are established. This is achieved by an accurate description of the maximal domain of an elliptic cone differential operator and its formal adjoint; thereby utilizing the concept of a discrete asymptotic type. From this description, the singular coefficients replacing the boundary traces in classical Green formulas are deduced.},
  language  = {en}
}
@unpublished{Witt2002,
  author    = {Witt, Ingo},
  title     = {Local asymptotic types},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26346},
  year      = {2002},
  abstract  = {The local theory of asymptotic types is elaborated. It appears as coordinate-free version of part of GOHBERG-SIGAL's theory of the inversion of finitely meromorphic, operator-valued functions at a point.},
  language  = {en}
}
@unpublished{Witt2002,
  author    = {Witt, Ingo},
  title     = {A calculus for a class of finitely degenerate pseudodifferential operators},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26246},
  year      = {2002},
  abstract  = {For a class of degenerate pseudodifferential operators, local parametrices are constructed. This is done in the framework of a pseudodifferential calculus upon adding conditions of trace and potential type, respectively, along the boundary on which the operators degenerate.},
  language  = {en}
}
@unpublished{Witt2001,
  author    = {Witt, Ingo},
  title     = {Asymptotic algebras},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26069},
  year      = {2001},
  abstract  = {The concept of asymptotic type that primarily appears in singular and asymptotic analysis is developed. Especially, asymptotic algebras are introduced.},
  language  = {en}
}
@unpublished{Witt1999,
  author    = {Witt, Ingo},
  title     = {On the factorization of meromorphic Mellin symbols},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-25427},
  year      = {1999},
  abstract  = {It is prooved that mermorphic, parameter-dependet elliptic Mellin symbols can be factorized in a particular way. The proof depends on the availability of logarithms of pseudodifferential operators. As a byproduct, we obtain a characterization of the group generated by pseudodifferential operators admitting a logarithm. The factorization has applications to the theory os pseudodifferential operators on spaces with conical singularities, e.g., to the index theory and the construction of various sub-calculi of the cone calculus.},
  language  = {en}
}
@unpublished{XiaochunWitt2002,
  author    = {Xiaochun, Liu and Witt, Ingo},
  title     = {Pseudodifferential calculi on the half-line respecting prescribed asymptotic types},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26255},
  year      = {2002},
  abstract  = {Contents: 1. Introduction 2. Preliminaries 3. Basic Elements of the Calculus 4. Further Elements of the Calculus},
  language  = {en}
}
@unpublished{XiaochunWitt2001,
  author    = {Xiaochun, Liu and Witt, Ingo},
  title     = {Asymptotic expansions for bounded solutions to semilinear Fuchsian equations},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-25912},
  year      = {2001},
  abstract  = {It is shown that bounded solutions to semilinear elliptic Fuchsian equations obey complete asymptoic expansions in terms of powers and logarithms in the distance to the boundary. For that purpose, Schuze's notion of asymptotic type for conormal asymptotics close to a conical point is refined. This in turn allows to perform explicit calculations on asymptotic types - modulo the resolution of the spectral problem for determining the singular exponents in the asmptotic expansions.},
  language  = {en}
}