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On a superatomic Boolean algebra which is not generated by a well-founded sublattice
Authors:Uri Abraham  Matatyahu Rubin  Robert Bonnet
Institution:(1) Department of Mathematics, Ben Gurion University of the Negev, 84105 Beer Sheva, Israel;(2) Laboratoire de Mathématiques, Université de Savoie, Le Bourget-du-Lac, France
Abstract:Let b denote the unboundedness number of ωω. That is, b is the smallest cardinality of a subset 
$$F \subseteq \omega ^\omega  $$
such that for everyg∈ωω there isf ∈ F such that {n: g(n) ≤ f(n)}is infinite. A Boolean algebraB is wellgenerated, if it has a well-founded sublatticeL such thatL generatesB. We show that it is consistent with ZFC that 
$$\aleph _1< 2^{\aleph _0 }  = b$$
, and there is a Boolean algebraB such thatB is not well-generated, andB is superatomic with cardinal sequence 〈ℵ0, ℵ1, ℵ1, 1〉. This result is motivated by the fact that if the cardinal sequence of a Boolean algebraB is 〈ℵ0, ℵ0, λ, 1〉, andB is not well-generated, then λ≥b.
Keywords:
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