This work presents results on solutions to the one-dimensional damped wave equation, also called telegrapher's equation, when the initial conditions are general distributions. We make a complete deduction of its fundamental solutions, both for positive and negative times. To obtain them we only use self-similarity arguments and distributional calculus, making no use of Fourier or Laplace transforms. We next use these fundamental solutions to prove both the existence and the uniqueness of solutions to the distributional initial value problem. As applications we recover the semi-group property for initial data in classical function spaces, and we find the probability distribution function for a recent financial model of evolution of prices.
Submitted March 13, 2020. Published December 26, 2020.
Math Subject Classifications: 35A08, 35L05, 35Q91.
Key Words: Partial Differential equations; damped wave equation; distributional solution; initial value problem.
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| Marc Nualart |
Department of Mathematics
Imperial College London
London, SW7 2AZ, UK
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