In mathematics, and especially general topology, the interlocking interval topology is an example of a topology on the set S := R+ \ Z+, i.e. the set of all positive real numbers that are not positive whole numbers.
[1] The open sets in this topology are taken to be the whole set S, the empty set ∅, and the sets generated by The sets generated by Xn will be formed by all possible unions of finite intersections of the Xn.
[2]