DOIAbstract
AbstractLet D be a directed set without last element. Call an ultrafilter p on D cofinal if every set in p is cofinal in D. We calculate the cardinality of the set of all cofinal ultrafilters on D
AbstractLet D be a directed set without last element. Call an ultrafilter p on D cofinal if every set in p is cofinal in D. We calculate the cardinality of the set of all cofinal ultrafilters on D
Abstract. Two classes of ultrafilters on natural numbers are presented which are determined by the s...
Abstract. Via two short proofs and three constructions, we show how to increase the model-theoretic ...
We define the notion of an ultrafilter on a set, and present three applications. The first is an alt...
. We prove some restrictions on the possible cofinalities of ultrapowers of the natural numbers wit...
summary:We shall show that there is an ultrafilter on singular $\kappa$ with countable cofinality, w...
This article surveys results regarding the Tukey theory of ultrafilters on countable base sets. The ...
• Definition. A quasiorder is a set with a transitive reflex-ive relation (denoted by ≤ by default)....
Abstract. We investigate the structure of the Tukey types of ultrafilters on countable sets partiall...
AbstractAn important application of ultrafilters is in the ultraproduct construction in model theory...
We prove the following: Theorem A. If D is a (λ +, κ)-regular ultrafilter, then either (a) D is (λ, ...
AbstractWe study Tukey types of ultrafilters on ω, focusing on the question of when Tukey reducibili...
Abstract. An ultrafilter U on a countable base set B has continuous Tukey reductions if whenever an ...
Abstract. We study Tukey types of ultrafilters on ω, focusing on the question of when Tukey reducibi...
AbstractLet μκ denote the space of uniform ultrafilters on κ, and let λ be a cardinal. Uϵμκ is said ...
Ultrafilters are very important mathematical objects in mathematical research [6, 22, 23]. There are...
Abstract. Two classes of ultrafilters on natural numbers are presented which are determined by the s...
Abstract. Via two short proofs and three constructions, we show how to increase the model-theoretic ...
We define the notion of an ultrafilter on a set, and present three applications. The first is an alt...
. We prove some restrictions on the possible cofinalities of ultrapowers of the natural numbers wit...
summary:We shall show that there is an ultrafilter on singular $\kappa$ with countable cofinality, w...
This article surveys results regarding the Tukey theory of ultrafilters on countable base sets. The ...
• Definition. A quasiorder is a set with a transitive reflex-ive relation (denoted by ≤ by default)....
Abstract. We investigate the structure of the Tukey types of ultrafilters on countable sets partiall...
AbstractAn important application of ultrafilters is in the ultraproduct construction in model theory...
We prove the following: Theorem A. If D is a (λ +, κ)-regular ultrafilter, then either (a) D is (λ, ...
AbstractWe study Tukey types of ultrafilters on ω, focusing on the question of when Tukey reducibili...
Abstract. An ultrafilter U on a countable base set B has continuous Tukey reductions if whenever an ...
Abstract. We study Tukey types of ultrafilters on ω, focusing on the question of when Tukey reducibi...
AbstractLet μκ denote the space of uniform ultrafilters on κ, and let λ be a cardinal. Uϵμκ is said ...
Ultrafilters are very important mathematical objects in mathematical research [6, 22, 23]. There are...
Abstract. Two classes of ultrafilters on natural numbers are presented which are determined by the s...
Abstract. Via two short proofs and three constructions, we show how to increase the model-theoretic ...
We define the notion of an ultrafilter on a set, and present three applications. The first is an alt...
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