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On the Wiener-Hopf factorization for Levy processes with bounded positive jumps

We study the Wiener-Hopf factorization for Levy processes with bounded positive jumps and arbitrary negative jumps. Using the results from the theory of entire functions of Cartwright class we prove that the positive Wiener-Hopf factor can be expressed as an infinite product in terms of the solutions to the equation $ψ(z)=q$, where $ψ$ is the Laplace exponent of the process. Under some additional regularity assumptions on the Levy measure we obtain an asymptotic expression for these solutions, which is important for numerical computations. In the case when the process is spectrally negative with bounded jumps, we derive a series representation for the scale function in terms of the solutions to the equation $ψ(z)=q$. To illustrate possible applications we discuss the implementation of numerical algorithms and present the results of several numerical experiments.