Results 1 to 10 of about 1,955 (244)

Polynomial Approximation on Unbounded Subsets, Markov Moment Problem and Other Applications [PDF]

Mathematics, 2020
This paper starts by recalling the author’s results on polynomial approximation over a Cartesian product A of closed unbounded intervals and its applications to solving Markov moment problems. Under natural assumptions, the existence and uniqueness of the solution are deduced.
Octav Olteanu, Olteanu Octav
exaly   +5 more sources

On Markov Moment Problem, Polynomial Approximation on Unbounded Subsets, and Mazur–Orlicz Theorem [PDF]

Symmetry, 2021
We review earlier and recent results on the Markov moment problem and related polynomial approximation on unbounded subsets. Such results allow proving the existence and uniqueness of the solutions for some Markov moment problems. This is the first aim of the paper.
Octav Olteanu, Olteanu Octav
exaly   +3 more sources

On Undecidability of Finite Subsets Theory for Torsion Abelian Groups

Mathematics, 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.
S M Dudakov
exaly   +4 more sources

Polynomial Approximation on Unbounded Subsets and the Markov Moment Problem

International Journal of Analysis and Applications, 2013
We start this review paper by recalling some known and relatively recent results in polynomial approximation on unbounded subsets. These results allow approximation of nonnegative continuous functions with compact support contained in the first quadrant by sums of tensor products of positive polynomials in each separate variable, on the positive ...
Octav Olteanu
core   +5 more sources

Semilinear elliptic problems on unbounded subsets of the Heisenberg group

Electronic Journal of Differential Equations, 2001
The author studies the existence of solutions for a Dirichlet problem of the equation \[ -\Delta_H u=f(u)\tag{1} \] on a (generally unbounded) domain of \(H^N\), where \(H^N\) be the space \(\mathbb{R}^N \times\mathbb{R}^N \times\mathbb{R}\) equipped with group operation \[ \eta=(\alpha, \beta,\tau),\quad \eta\cdot \eta'=\bigl( \alpha +\alpha', \beta ...
K. Tintarev
core   +4 more sources

Lattice uniformities inducing unbounded convergence

Journal of Mathematical Analysis and Applications, 2023
A net (xγ)γ∈Γ in a locally solid Riesz space (X,τ) is said to be unbounded τ-convergent to x if |xγ−x|∧u⟶τ0 for all u∈X+. We recall that there is a locally solid linear topology uτ on X such that unbounded τ-convergence coincides with uτ-convergence.
Emmanuel Chetcuti, Hans Weber
exaly   +2 more sources

On the existence of large subsets of [λ] κ which contain no unbounded non-stationary subsets

Archive for Mathematical Logic, 2002
Here we deal with some problems posed by Matet. The first section deals with the existence of stationary subsets of [lambda]^{
Saharon Shelah
exaly   +3 more sources

Forcing closed unbounded subsets of ω2

Annals of Pure and Applied Logic, 2001
The author shows that there is no satisfactory first-order characterization of subsets of \(\omega_2\) that have closed unbounded subsets in \(\omega_1\) and \(\omega_2\) and GCH-preserving outermodels. The author shows that this ``anti-characterization'' result extends to subsets of successors of regular uncountable cardinals.
exaly   +3 more sources

SOME PLANCHEREL IDENTITIES FOR UNBOUNDED SUBSETS OF $$\mathbb {R}$$ IN DUALITY

Journal of Mathematical Sciences
In relation to Fuglede's conjecture, we establish several Plancherel-type identities and demonstrate the surjectivity of the Fourier transform between certain unbounded tiling sets of $\mathbb{R}$ that are in duality. In the terminology commonly used in the context of Fuglede's conjecture, our result states that an open set tiles $\mathbb{R}$ by the ...
Dorin Ervin Dutkay
exaly   +3 more sources

Weighted Polynomial Approximation of Entire Functions on Unbounded Subsets of the Complex Plane

Canadian Mathematical Bulletin, 1993
AbstractWe study the asymptotic behavior of the n-widths of a class of entire functions in weighted approximation on subsets of the complex plane.
H. N. Mhaskar
openaire   +2 more sources