Structure of Upper and Lower Approximation Spaces of Infinite Sets
D. S. Malik, John Nelson Mordeson · Studies in fuzziness and soft computing · 2002
We determine structural properties of upper and lower approximation spaces. In particular, we show that an upper approximation space is a union of its primary subspaces if and only if it is benign. We also show that in a principle upper approximation space which is not primary, the prime and maximal subspaces coincide.