TY  - JOUR
A1  - Witt, Ingo
T1  - Local asymptotic types
N2  - 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
Y1  - 2004
SN  - 0025-2611
ER  - 
TY  - JOUR
A1  - Liu, Xiaochun
A1  - Witt, Ingo
T1  - Pseudodifferential calculi on the half-line respecting prescribed asymptotic types
N2  - 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.
Y1  - 2004
SN  - 0378-620X
ER  - 
TY  - JOUR
A1  - Yin, H. C.
A1  - Witt, Ingo
T1  - Global singularity structure of weak solutions to 3-D semilinear dispersive wave equations with discontinuous initial data
N2  - 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
Y1  - 2004
SN  - 0022-0396
ER  -