As described in more detail in Section 2.1, in RR, the DRT is obtained by minimizing the sum of squared residuals plus an additional term penalizing "ridges" in 𝛾(log 𝜏) . Namely, if 𝒙 is (loosely) defined as the vector of the DRT at discrete log 𝜏 values (a more precise definition and more details are given in Section 2.1.1.1), DRT deconvolution through RR requires solving the following problem :