When moving from metric spaces to general topological spaces, these objects must be generalized to nets. The Borel-Cantelli (-5[1])lemma follows by constructing one of these objects containing events and then applying continuity of the measure. In general, compactness in the sense of a finite subcover for every open cover is independent of a type of compactness named for these objects. The (*) Cantor set is homeomorphic to the space of these objects over the discrete space {0, 1} (“zero comma one”), and Cantor’s diagonalization argument builds one of these (-5[1])objects out of countably many of them where the new one differs from each original in at least one place. If a is one of these objects, one might say “a sub n approaches x as n approaches infinity”. For 10 points, a collection of objects indexed by the natural numbers is referred to by what term that titles an example named for Fibonacci? ■END■ (10[2])