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A forcing construction of thin-tall Boolean algebras

100%

Martínez J. C.

Fundamenta Mathematicae

1999

tom 159

nr 2

99-113

It was proved by Juhász and Weiss that for every ordinal α with ${0 < α < ω_2}$ there is a superatomic Boolean algebra of height α and width ω. We prove that if κ is an infinite cardinal such that $κ^{< κ} = κ$ and α is an ordinal such that $0 < α < κ^{++}$, then there is a cardinal-preserving partial order that forces the existence of a superatomic Boolean algebra of height α and width κ. Furthermore, iterating this forcing through all $α < κ^{++}$, we obtain a notion of forcing that preserves cardinals and such that in the corresponding generic extension there is a superatomic Boolean algebra of height α and width κ for every $α < κ^{++}$. Consistency for specific κ, like $ω_1$, then follows as a corollary.

On a class of topological spaces with a Scott sentence

44%

Martínez J. C.

Fundamenta Mathematicae

1988

tom 129

nr 2

69-81

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2 Fundamenta Mathematicae

2 Martínez J. C.

1 1999

1 1988

Wyniki wyszukiwania

A forcing construction of thin-tall Boolean algebras

On a class of topological spaces with a Scott sentence