Type of subset of the natural numbers
In mathematics, a syndetic set is a subset of the natural numbers having the property of "bounded gaps": that the sizes of the gaps in the sequence of natural numbers is bounded.
Definition.
A set formula_1 is called syndetic if for some finite subset formula_2 of formula_3
formula_4
where formula_5. Thus syndetic sets have "bounded gaps"; for a syndetic set formula_6, there is an integer formula_7 such that formula_8 for any formula_9.