The topological density of a Boolean algebra is the minimal cardinal such that can be covered by ultrafilters.
We give a simplified proof of a theorem of M. Rabus and S. Shelah claiming that for each cardinal there is a c.c.c Boolean algebra with topological density .
M. Rabus, S. Shelah, Topological density of ccc Boolean algebras - every cardinality occurs, Proc. Am. Math. Soc. Vol 127 (1999). No 9. pp. 2573-2581.
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