Szukana fraza: [Abstract = "In the paper, the problem of source function reconstruction in a differential equation of the parabolic type is investigated.Using the semigroup representation of trajectories of dynamical systems, we build a finite\-step iterative procedure forsolving this problem. The algorithm originates from the theory of closed\-loop control \(the method of extremal shift\). Atevery step of the algorithm, the sum of a quality criterion and a linear penalty term is minimized. This procedure is robustto perturbations in problems data."]