Displaying similar documents to “Cardinal invariants of universals”

On monotone Lindelöfness of countable spaces

Ronnie Levy, Mikhail Matveev (2008)

Commentationes Mathematicae Universitatis Carolinae

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A space is monotonically Lindelöf (mL) if one can assign to every open cover 𝒰 a countable open refinement r ( 𝒰 ) so that r ( 𝒰 ) refines r ( 𝒱 ) whenever 𝒰 refines 𝒱 . We show that some countable spaces are not mL, and that, assuming CH, there are countable mL spaces that are not second countable.

Topologies and bornologies determined by operator ideals, II

Ngai-Ching Wong (1994)

Studia Mathematica

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Let be an operator ideal on LCS’s. A continuous seminorm p of a LCS X is said to be - continuous if Q ̃ p ∈ i n j ( X , X ̃ p ) , where X ̃ p is the completion of the normed space X p = X / p - 1 ( 0 ) and Q ̃ p is the canonical map. p is said to be a Groth()- seminorm if there is a continuous seminorm q of X such that p ≤ q and the canonical map Q ̃ p q : X ̃ q → X ̃ p belongs to ( X ̃ q , X ̃ p ) . It is well known that when is the ideal of absolutely summing (resp. precompact, weakly compact) operators, a LCS X is a nuclear (resp. Schwartz, infra-Schwartz) space if and only...

Universal spaces for manifolds equipped with an integral closed k -form

Hông-Vân Lê (2007)

Archivum Mathematicum

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In this note we prove that any integral closed k -form φ k , k ≥ 3 , on a m-dimensional manifold M m , m ≥ k , is the restriction of a universal closed k -form h k on a universal manifold U d ( m , k ) as a result of an embedding of M m to U d ( m , k ) .