On the Kuratowski Closure-Complement Problem
نویسندگان
چکیده
In this article we formalize the Kuratowski closure-complement result: there is at most 14 distinct sets that one can produce from a given subset A of a topological space T by applying closure and complement operators and that all 14 can be obtained from a suitable subset of R, namely KuratExSet = {1} ∪Q(2, 3) ∪ (3, 4) ∪ (4,∞). The second part of the article deals with the maximal number of distinct sets which may be obtained from a given subset A of T by applying closure and interior operators. The subset KuratExSet of R is also enough to show that 7 can be achieved.
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