IX: 37, 556-564, LNM 465 (1975) MEYER, Paul-André Retour aux retournements (Markov processes, General theory of processes) The first part of the talk is devoted to an important correction to the theorem on p.285 of 814 (Azéma's theory of cooptional and coprevisible sets and its application to Markov processes): the definition of left additive functionals should allow an a.s. explosion at time 0 for initial points belonging to a polar set. The second part belongs to the general theory of processes: if the index set is not the right half-line as usual but the left half-line, the section and projection theorems must be modified in a not quite trivial way Comment: See Chapter XXVIII of Dellacherie-Maisonneuve-Meyer Probabilités et potentiel Keywords: Time reversal, Cooptional processes, Coprevisible processes, Homogeneous processes Nature: Exposition, Original additions Retrieve article from Numdam