Topological approaches to generalized rough multisets

This paper proposes new definitions of lower and upper mset approximations, which are basic concepts of the rough mset theory. These definitions come naturally from the concepts of multiset topologies and of ambiguity introduced in this paper. The new definitions are compared to classical definitions and are shown to be more general. In the sense, they are the only ones which can be used for any type of indiscernibility or similarity mset relation.