@article{Witt2004,
  author    = {Witt, Ingo},
  title     = {Local asymptotic types},
  issn      = {0025-2611},
  year      = {2004},
  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}
}
@article{LiuWitt2004,
  author    = {Liu, Xiaochun and Witt, Ingo},
  title     = {Pseudodifferential calculi on the half-line respecting prescribed asymptotic types},
  issn      = {0378-620X},
  year      = {2004},
  abstract  = {Given asymptotics types P, Q, pseudodifferential operators A is an element of L-cl(mu) (R+) are constructed in such a way that if u(t) possesses conormal asymptotics of type P as t --> +0, then Au(t) possesses conormal asymptotics of type Q as t --> +0. This is achieved by choosing the operators A in Schulze's cone algebra on the half-line R+, controlling their complete Mellin symbols {sigma(M)(u-j) (A); j is an element of N}, and prescribing the mapping properties of the residual Green operators. The constructions lead to a coordinate invariant calculus, including trace and potential operators at t = 0, in which a parametrix construction for the elliptic elements is possible. Boutet de Monvel's calculus for pseudodifferential boundary problems occurs as a special case when P = Q is the type resulting from Taylor expansion at t = 0.},
  language  = {en}
}
@article{YinWitt2004,
  author    = {Yin, H. C. and Witt, Ingo},
  title     = {Global singularity structure of weak solutions to 3-D semilinear dispersive wave equations with discontinuous initial data},
  issn      = {0022-0396},
  year      = {2004},
  abstract  = {We study the global singularity structure of solutions to 3-D semilinear wave equations with discontinuous initial data. More precisely, using Strichartz' inequality we show that the solutions stay conormal after nonlinear interaction if the Cauchy data are conormal along a circle. (C) 2003 Elsevier Inc. All rights reserved},
  language  = {en}
}