ABSTRACT
This chapter uses rough sets to deal with the problem of ambiguity or imprecision. It shows one of the possibilities of how to assess (measure) ambiguities or imprecisions that have to be dealt with if we wish to determine some categories on the basis of connections (social interactions) with other categories in social networks. One of the possibilities is to use rough sets as proposed by Z. Pawlak as a tool to deal with rough (ambiguous, imprecise) categories. The main idea is to approximate a given set by a pair of sets, called the lower and upper approximation of this set. Rough sets were defined on the basis of indiscernibility relation of objects in some universe of discourse. Theoretical foundations given in the chapter are supplemented with a real-life examples concerning the assessment and cohesion of co-authorships between research teams.
