On collections of almost disjoint families
Displaying 61 – 80 of 332
On compact spaces carrying Radon measures of uncountable Maharam type
David Fremlin (1997)
Fundamenta Mathematicae
If Martin’s Axiom is true and the continuum hypothesis is false, and X is a compact Radon measure space with a non-separable space, then there is a continuous surjection from X onto .
On complemented copies of c₀(ω₁) in C(Kⁿ) spaces
Leandro Candido, Piotr Koszmider (2016)
Studia Mathematica
Given a compact Hausdorff space K we consider the Banach space of real continuous functions C(Kⁿ) or equivalently the n-fold injective tensor product or the Banach space of vector valued continuous functions C(K,C(K,C(K...,C(K)...). We address the question of the existence of complemented copies of c₀(ω₁) in under the hypothesis that C(K) contains such a copy. This is related to the results of E. Saab and P. Saab that contains a complemented copy of c₀ if one of the infinite-dimensional Banach...
On completely Ramsey sets
Szymon Plewik (1987)
Fundamenta Mathematicae
On completeness and direction in fuzzy relational systems.
Pedro J. Burillo López, Ramón Fuentes-González, León A. González Sotos (1998)
Mathware and Soft Computing
The concepts of bounded subset, complete subset and directed subset, wich are well known in the context of partially ordered sets (X,≤), are extended in order to become appliable, with coherence, in fuzzy relational systems (X,R). The properties of these generalized structures are analyzed and operative exemples of them are presented.
On complexity of a set of norms in Banach spaces
Robert Kaufman (2003)
Acta Universitatis Carolinae. Mathematica et Physica
On concentrated sets and N-sets
N. N. Kholshchevnikova (1990)
Acta Universitatis Carolinae. Mathematica et Physica
On continuity of measurable group representations and homomorphisms
Yulia Kuznetsova (2012)
Studia Mathematica
Let G be a locally compact group, and let U be its unitary representation on a Hilbert space H. Endow the space ℒ(H) of bounded linear operators on H with the weak operator topology. We prove that if U is a measurable map from G to ℒ(H) then it is continuous. This result was known before for separable H. We also prove that the following statement is consistent with ZFC: every measurable homomorphism from a locally compact group into any topological group is continuous.
On countable cofinality and decomposition of definable thin orderings
Vladimir Kanovei, Vassily Lyubetsky (2016)
Fundamenta Mathematicae
We prove that in some cases definable thin sets (including chains) of Borel partial orderings are necessarily countably cofinal. This includes the following cases: analytic thin sets, ROD thin sets in the Solovay model, and Σ¹₂ thin sets under the assumption that for all reals x. We also prove that definable thin wellorderings admit partitions into definable chains in the Solovay model.
On countable von Neumann regular rings
Jan Trlifaj (1991)
Czechoslovak Mathematical Journal
On decomposing the plane into connected or one-to-one curves
Jack Ceder (1973)
Fundamenta Mathematicae
On dense subsets of rational numbers
Jacek Cichoń (2001)
Acta Universitatis Carolinae. Mathematica et Physica
On determination of a cyclic order
Vítězslav Novák, Miroslav Novotný (1983)
Czechoslovak Mathematical Journal
On diamond sequences
Pierre Matet (1988)
Fundamenta Mathematicae
On elementary cuts in models of arithmetic
Henryk Kotlarski (1983)
Fundamenta Mathematicae
On equivalence relations second order definable over H(κ)
Saharon Shelah, Pauli Vaisanen (2002)
Fundamenta Mathematicae
Let κ be an uncountable regular cardinal. Call an equivalence relation on functions from κ into 2 second order definable over H(κ) if there exists a second order sentence ϕ and a parameter P ⊆ H(κ) such that functions f and g from κ into 2 are equivalent iff the structure ⟨ H(κ), ∈, P, f, g ⟩ satisfies ϕ. The possible numbers of equivalence classes of second order definable equivalence relations include all the nonzero cardinals at most κ⁺. Additionally, the possibilities are closed under unions...
On expansions of β-models
J. Bilý, L. Bukovský (1974)
Fundamenta Mathematicae
On exposed semigroup homomorphisms.
B. Fuchssteiner (1976/1977)
Semigroup forum
On extension of the group operation over the Čech-Stone compactification
Jan Jełowicki (1993)
Colloquium Mathematicae
The convolution of ultrafilters of closed subsets of a normal topological group is considered as a substitute of the extension onto of the group operation. We find a subclass of ultrafilters for which this extension is well-defined and give some examples of pathologies. Next, for a given locally compact group and its dense subgroup , we construct subsets of β algebraically isomorphic to . Finally, we check whether the natural mapping from β onto β is a homomorphism with respect to the extension...
On families of Lindelöf and related subspaces of
Lúcia Junqueira, Piotr Koszmider (2001)
Fundamenta Mathematicae
We consider the families of all subspaces of size ω₁ of (or of a compact zero-dimensional space X of weight ω₁ in general) which are normal, have the Lindelöf property or are closed under limits of convergent ω₁-sequences. Various relations among these families modulo the club filter in are shown to be consistently possible. One of the main tools is dealing with a subspace of the form X ∩ M for an elementary submodel M of size ω₁. Various results with this flavor are obtained. Another tool used...