Assertion: set's number | /r/HasProperty | natural
Facets:
Source sentences:
text: Every infinite set which can be enumerated by natural numbers is the same size (cardinality) as N, and is said to be countable.
text: The connection between the empty set and zero goes further, however: in the standard set-theoretic definition of natural numbers, sets are used to model the natural numbers.
text: Then the set {I n : n is a natural number}, where I n is the set of natural numbers below n, is a chain in this ordering, as it is totally ordered under inclusion: If n≤k, then I n is a subset of I k .