(eng): Marginal problem in the framework of evidence theory is introduced in a way analogous to probabilistic one, to address the question of whether or not a common extension exists for a given set of marginal basic assignments. Similarities between these two problem types are demonstrated, concerning necessary condition for the existence of an extension and sets of all solutions. Finally, product extension of the set of marginal basic assignments is introduced as a tool for the expression of a representative in a closed form.