Characterizations of an MW-topological rough set structure


Sang-Eon Han




Regarding the study of digital topological rough set structures, the present paper explores some mathematical and systemical structures of the Marcus-Wyse (MW-, for brevity) topological rough set structures induced by the locally finite covering approximation (LFC-, for brevity) space (R 2 , C) (see Proposition 3.4 in this paper), where R 2 is the 2-dimensional Euclidean space. More precisely, given the LFC-space (R 2 , C), based on the set of adhesions of points in R 2 inducing certain LFC-rough concept approximations, we systematically investigate various properties of the MW-topological rough concept approximations (D − M , D + M) derived from this LFC-space (R 2 , C). These approaches can facilitate the study of an estimation of roughness in terms of an MW-topological rough set. In the present paper each of a universe U and a target set X(⊆ U) need not be finite and further, a covering C is locally finite. In addition, when regarding both an M-rough set and an MW-topological rough set in Sections 3, 4, and 5, the universe U(⊂ R 2) is assumed to be the set R 2 or a compact subset of R 2 or a certain set containing the union of all adhesions of x ∈ X (see Remark 3.6).