@unpublished{WenyiTianbo2005,
  author    = {Wenyi, Chen and Tianbo, Wang},
  title     = {The hypoellipticity of differential forms on closed manifolds},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-29803},
  year      = {2005},
  abstract  = {In this paper we consider the hypo-ellipticity of differential forms on a closed manifold.The main results show that there are some topological obstruct for the existence of the differential forms with hypoellipticity.},
  language  = {de}
}
@unpublished{WeskeRinderleMaToumanietal.2013,
  author    = {Weske, Mathias and Rinderle-Ma, Stefanie and Toumani, Farouk and Wolf, Karsten},
  title     = {Special section on BPM 2011 conference. - Special Issue},
  series = {Information systems},
  volume    = {38},
  journal   = {Information systems},
  number    = {4},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0306-4379},
  doi       = {10.1016/j.is.2013.01.003},
  pages     = {545 -- 546},
  year      = {2013},
  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@unpublished{Witt2003,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@unpublished{Witt2002,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     = {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@unpublished{Witt2001,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{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{XiaochunSchulze2004,
  author    = {Xiaochun, Liu and Schulze, Bert-Wolfgang},
  title     = {Boundary value problems in edge representation},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-26746},
  year      = {2004},
  abstract  = {Edge representations of operators on closed manifolds are known to induce large classes of operators that are elliptic on specific manifolds with edges, cf. [9]. We apply this idea to the case of boundary value problems. We establish a correspondence between standard ellipticity and ellipticity with respect to the principal symbolic hierarchy of the edge algebra of boundary value problems, where an embedded submanifold on the boundary plays the role of an edge. We first consider the case that the weight is equal to the smoothness and calculate the dimensions of kernels and cokernels of the associated principal edge symbols. Then we pass to elliptic edge operators for arbitrary weights and construct the additional edge conditions by applying relative index results for conormal symbols.},
  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}
}