No countable tightness in beta omega

Consider , the Stone-Cech compactification of the countable discrete space . It has no non-trivial convergent sequence. As a result, it fails to have any convergence properties that require the existence of non-trivial convergent sequences. For example, is not a sequential space (see Fact 7 found here). Any sequential space has countable tightness (see here). We show that even fails to have countable tightness. The proof is based on a theorem that says that countable tightness is preserved by...