  Some abstract argumentation approaches consider that arguments have a degree
of uncertainty, which impacts on the degree of uncertainty of the extensions
obtained from a abstract argumentation framework (AAF) under a semantics. In
these approaches, both the uncertainty of the arguments and of the extensions
are modeled by means of precise probability values. However, in many real life
situations the exact probabilities values are unknown and sometimes there is a
need for aggregating the probability values of different sources. In this
paper, we tackle the problem of calculating the degree of uncertainty of the
extensions considering that the probability values of the arguments are
imprecise. We use credal sets to model the uncertainty values of arguments and
from these credal sets, we calculate the lower and upper bounds of the
extensions. We study some properties of the suggested approach and illustrate
it with an scenario of decision making.
