Results 11 to 20 of about 208,928 (143)

On Undecidability of Finite Subsets Theory for Torsion Abelian Groups

open access: yesMathematics, 2022
Let M be a commutative cancellative monoid with an element of infinite order. The binary operation can be extended to all finite subsets of M by the pointwise definition. So, we can consider the theory of finite subsets of M.
Sergey Mikhailovich Dudakov
doaj   +1 more source

On the Moment Problem and Related Problems

open access: yesMathematics, 2021
Firstly, we recall the classical moment problem and some basic results related to it. By its formulation, this is an inverse problem: being given a sequence (yj)j∈ℕn  of real numbers and a closed subset F⊆ℝn, n∈{1,2,…}, find a positive regular Borel ...
Octav Olteanu
doaj   +1 more source

Markov Moment Problem and Sandwich Conditions on Bounded Linear Operators in Terms of Quadratic Forms

open access: yesMathematics, 2022
As is well-known, unlike the one-dimensional case, there exist nonnegative polynomials in several real variables that are not sums of squares. First, we briefly review a method of approximating any real-valued nonnegative continuous compactly supported ...
Octav Olteanu
doaj   +1 more source

Closeness and linkness in balleans

open access: yesМатематичні Студії, 2020
A set $X$ endowed with a coarse structure is called ballean or coarse space. For a ballean $(X, \mathcal{E})$, we say that two subsets $A$, $B$ of $X$ are close (linked) if there exists an entourage $E\in \mathcal{E}$ such that $A\subseteq E [B]$, $B ...
I.V. Protasov, K. Protasova
doaj   +1 more source

Representations of bornologies

open access: yesApplied General Topology, 2022
Bornologies abstract the properties of bounded sets of a metric space. But there are unbounded bornologies on a metric space like $\mathcal{P}(\RR)$ with the Euclidean metric.
Homeira Pajoohesh
doaj   +1 more source

Convexity, Markov Operators, Approximation, and Related Optimization

open access: yesMathematics, 2022
The present review paper provides recent results on convexity and its applications to the constrained extension of linear operators, motivated by the existence of subgradients of continuous convex operators, the Markov moment problem and related Markov ...
Octav Olteanu
doaj   +1 more source

Extremal balleans

open access: yesApplied General Topology, 2019
A ballean (or coarse space) is a set endowed with a coarse structure. A ballean X is called normal if any two asymptotically disjoint subsets of X are asymptotically separated.
Igor Protasov
doaj   +1 more source

Three Representations for Set Partitions

open access: yesIEEE Access, 2021
The Set Partitioning Problem (SPP) aims to obtain non-empty disjoint subsets of objects such that their union equals the whole set of objects, and the partition meets some prespecified criteria.
Jose Torres-Jimenez   +4 more
doaj   +1 more source

The structure of normal subsets of polyhedral cone

open access: yesҚарағанды университетінің хабаршысы. Математика сериясы, 2017
The structure of normal convex subsets of polyhedral cone K in normalized space is in investigated. The normality of the subset Ω ⊂ K (in the sense of the cone K) is determined by the condition Ω - K ∩K = Ω (a line over a set means taking a topological ...
T.Kh. Makazhanova   +2 more
doaj   +1 more source

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