Abstract
In this paper, the Cauchy problem for the spatially one-dimensional distributed order diffusion-wave equation
is considered. Here, the time-fractional derivative D β t is understood in the Caputo sense and p(β) is a non-negative weight function with support somewhere in the interval [0, 2]. By employing the technique of the Fourier and Laplace transforms, a representation of the fundamental solution of the Cauchy problem in the transform domain is obtained. The main focus is on the interpretation of the fundamental solution as a probability density function of the space variable x evolving in time t. In particular, the fundamental solution of the time-fractional distributed order wave equation (p(β) ≡ 0, 0 ≤ β < 1) is shown to be non-negative and normalized. In the proof, properties of the completely monotone functions, the Bernstein functions, and the Stieltjes functions are used.
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Dedicated to Professor Francesco Mainardi on the occasion of his 70th anniversary
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Gorenflo, R., Luchko, Y. & Stojanović, M. Fundamental solution of a distributed order time-fractional diffusion-wave equation as probability density. fcaa 16, 297–316 (2013). https://doi.org/10.2478/s13540-013-0019-6
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DOI: https://doi.org/10.2478/s13540-013-0019-6