Superatomic Boolean algebras constructed from strongly unbounded functions
Abstract: Using Koszmider's strongly unbounded functions, we show the following consistency result: Suppose that $\kappa,\lambda$ are infinite cardinals such that $\kappa{+++} \leq \lambda$, $\kappa{<\kappa}=\kappa$ and $2{\kappa}= \kappa+$, and $\eta$ is an ordinal with $\kappa+\leq \eta <\kappa{++}$ and $cf(\eta) = \kappa+$. Then, in some cardinal-preserving generic extension there is a superatomic Boolean algebra $B$ such that - $ht(B) = \eta + 1$, - the cardinality of the $\alpha$th level of $B$ is $\kappa$ for every $\alpha <\eta$, - and the cardinality of the $\eta$th level of $B$ is $\lambda$ Especially, $<{\omega}>{{\omega}_1}\concatenation <{\omega}_3>$ and $<{\omega}_1>{{\omega}_2}\concatenation <{\omega}_4>$ can be cardinal sequences of superatomic Boolean algebras.
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