Almost disjoint families: An application to linear algebra.
Almost disjoint families and “never” cardinal invariants
We define two cardinal invariants of the continuum which arise naturally from combinatorially and topologically appealing properties of almost disjoint families of sets of the natural numbers. These are the never soft and never countably paracompact numbers. We show that these cardinals must both be equal to under the effective weak diamond principle , answering questions of da Silva S.G., On the presence of countable paracompactness, normality and property in spaces from almost disjoint families,...
Almost disjoint families and property (a)
We consider the question: when does a Ψ-space satisfy property (a)? We show that if then the Ψ-space Ψ(A) satisfies property (a), but in some Cohen models the negation of CH holds and every uncountable Ψ-space fails to satisfy property (a). We also show that in a model of Fleissner and Miller there exists a Ψ-space of cardinality which has property (a). We extend a theorem of Matveev relating the existence of certain closed discrete subsets with the failure of property (a).
Almost every function is independent
Almost maximal ideals
Alternative model of fuzzy NTU coalitional game
One of the possible models of fuzzification of non-transferable utility (NTU) coalitional games was extensively treated in [4]. In this paper, we suggest an alternative structure of fuzzification of the NTU games, where for every coalition a fuzzy class of (generally crisp) sets of its admissible pay-off vectors is considered. It is shown that this model of a fuzzy coalitional game can be represented by a fuzzy class of deterministic NTU games, and its basic concepts like the superadditivity or...
Alternative set theory with elementary classes
In this paper we sketch the development and give a model of the formal version of a generalization of the Alternative Set Theory.
Ambiguity and stratification
Amenability and Ramsey theory
The purpose of this article is to connect the notion of the amenability of a discrete group with a new form of structural Ramsey theory. The Ramsey-theoretic reformulation of amenability constitutes a considerable weakening of the Følner criterion. As a by-product, it will be shown that in any non-amenable group G, there is a subset E of G such that no finitely additive probability measure on G measures all translates of E equally. The analysis of discrete groups will be generalized to the setting...
Amenability and Ramsey theory in the metric setting
Moore [Fund. Math. 220 (2013)] characterizes the amenability of the automorphism groups of countable ultrahomogeneous structures by a Ramsey-type property. We extend this result to the automorphism groups of metric Fraïssé structures, which encompass all Polish groups. As an application, we prove that amenability is a condition.
Amoeba relation and Galois-Tukey connections
Amorphe Potenzen kompakter Räume.
An abstract version of Sierpiński's theorem and the algebra generated by A and CA functions
We give an abstract version of Sierpiński's theorem which says that the closure in the uniform convergence topology of the algebra spanned by the sums of lower and upper semicontinuous functions is the class of all Baire 1 functions. Later we show that a natural generalization of Sierpiński's result for the uniform closure of the space of all sums of A and CA functions is not true. Namely we show that the uniform closure of the space of all sums of A and CA functions is a proper subclass of the...
An additive decomposition of fuzzy numbers
Hong and Do[4] improved Mareš[7] result about additive decomposition of fuzzy quantities concerning an equivalence relation. But there still exists an open question which is the limitation to fuzzy quantities on R (the set of real numbers) with bounded supports in the presented theory. In this paper we restrict ourselves to fuzzy numbers, which are fuzzy quantities of the real line R with convex, normalized and upper semicontinuous membership function and prove this open question.
An algebraic and logical approach to continuous images
An algebraic equivalent of a multiple choice axiom
An algorithm of calculation of lower solutions of fuzzy relational equations.
This paper deals with the problem of the determination of lower solutions of fuzzy relational equations. An algorithm of calculation of such a solution is presented.
An Algorithm to Compute theTransitive Closure, a Transitive Approximation and a Transitive Opening of a Fuzzy Proximity.
An alternative approach to rough sets
An alternative proof of Hill's criterion of freeness for Abelian groups.