His usage is correct. Cardinality refers to the size of any set. This includes finite, countable, and uncountable sets. The sequence of cardinal numbers is t

His usage is correct. Cardinality refers to the size of any set. This includes finite, countable, and uncountable sets. The sequence of cardinal numbers is transfinite: 0, 1, 2, ... , n, ..., aleph_0, aleph_1, ... http://en.wikipedia.org/wiki/Cardinality http://en.wikipedia.org/wiki/Cardinality http://en.wikipedia.org/wiki/Cardinal_number http://en.wikipedia.org/wiki/Cardinal_number