Inverse problem for the propagation equation of cosmic-ray electrons/positrons from dark matter

We discuss the possibility of solving the inverse problem for the propagation equation of the cosmic-ray electrons/positrons from decaying/annihilating dark matter, and show simple analytic formulae to reconstruct the source spectrum of the electrons/positrons from the observed flux. We also illustrate our approach by applying the obtained formula to the just released Fermi data as well as the new HESS data.