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Γ -limiti e minimi di Pareto

Roberto Peirone (1983)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

The notion of Γ -limit is extended from the case of functions with values in 𝐑 ¯ to the case of those with values in an arbitrary complete lattice and the problem of convergence of Pareto minima related to a convex cone is considered.

κ-compactness, extent and the Lindelöf number in LOTS

David Buhagiar, Emmanuel Chetcuti, Hans Weber (2014)

Open Mathematics

We study the behaviour of ℵ-compactness, extent and Lindelöf number in lexicographic products of linearly ordered spaces. It is seen, in particular, that for the case that all spaces are bounded all these properties behave very well when taking lexicographic products. We also give characterizations of these notions for generalized ordered spaces.

ω H-sets and cardinal invariants

Alessandro Fedeli (1998)

Commentationes Mathematicae Universitatis Carolinae

A subset A of a Hausdorff space X is called an ω H-set in X if for every open family 𝒰 in X such that A 𝒰 there exists a countable subfamily 𝒱 of 𝒰 such that A { V ¯ : V 𝒱 } . In this paper we introduce a new cardinal function t s θ and show that | A | 2 t s θ ( X ) ψ c ( X ) for every ω H-set A of a Hausdorff space X .

ω ω -directedness and a question of E. Michael

Peg Daniels (1995)

Commentationes Mathematicae Universitatis Carolinae

We define ω ω -directedness, investigate various properties to determine whether they have this property or not, and use our results to obtain easier proofs of theorems due to Laurence and Alster concerning the existence of a Michael space, i.eȧ Lindelöf space whose product with the irrationals is not Lindelöf.

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