Linear boundary value problems of elasticity describe the propagation
of time- harmonic waves outside of N parallel half-plane shaped cracks
in the Euclidian 3-space. Equivalent systems involving 6N Wiener-Hopf
equations are obtained for first, second and third kind conditions si
multaneously. To find explicit solutions, complex-valued matrix functi
ons with nonrational entries, are to be factorized in a generalized ma
nner. This is done for two double-knife screen crack problems in Part
II. Problems for waves in acoustics, hydro-and electrodynamics with an
analogous geometry for rigid walls, or perfectly conducting metallic
sheets, are contained in the problems formulated above: In Part II, fo
r pure Dirichlet-, or Neumann conditions, the corresponding (reduced)
Wiener-Hopf operator is seen to be invertible by an operator Neumann s
eries for all distances (not equal 0) between the N half-planes Sigma(
m).