Dempster-Shafer theory

The Dempster-Shafer theory is a mathematical theory of evidence that was introduced in the late Seventies by Glenn Shafer as a way of representing epistemic knowledge, starting from a sequence of seminal works of Arthur Dempster[?], Shafer's advisor. In this formalism the best representation of chance is a belief function (b.f.) rather than a Bayesian mass distribution. They assign probability values to sets of possibilities rather than single events: their appeal rests on the fact they naturally encode evidence in favor to propositions.