# zbMATH — the first resource for mathematics

The distributivity numbers of $$\mathcal{P}(\omega)$$/fin and its square. (English) Zbl 0943.03036
Authors’ summary: We show that in a model obtained by forcing with a countable support iteration of Mathias forcing of length $$\omega_{2}$$, the distributivity number of $${\mathcal{P}}(\omega)$$/fin is $$\omega_{2}$$, whereas the distributivity number of r.o.$$({\mathcal{P}}(\omega)$$/fin)$$^{2}$$ is $$\omega_{1}$$. This answers a problem of Balcar, Pelant and Simon, and others.

##### MSC:
 300000 Other combinatorial set theory 600000 Structure theory of Boolean algebras
Full Text: