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Results on spline-Fourier and Ciesielski-Fourier series

Ferenc Weisz (2006)

Banach Center Publications

Some recent results on spline-Fourier and Ciesielski-Fourier series are summarized. The convergence of spline Fourier series and the basis properties of the spline systems are considered. Some classical topics, that are well known for trigonometric and Walsh-Fourier series, are investigated for Ciesielski-Fourier series, such as inequalities for the Fourier coefficients, convergence a.e. and in norm, Fejér and θ-summability, strong summability and multipliers. The connection between Fourier series...

Resurgence of the Kontsevich-Zagier series

Ovidiu Costin, Stavros Garoufalidis (2011)

Annales de l’institut Fourier

The paper is concerned with the resurgence of the Kontsevich-Zagier series f ( q ) = n = 0 ( 1 - q ) ( 1 - q n ) We give an explicit formula for the Borel transform of the power series when q = e 1 / x from which its analytic continuation, its singularities (all on the positive real axis) and the local monodromy can be manifestly determined. We also give two formulas (one involving the Dedekind eta function, and another involving the complex error function) for the right, left and median summation of the Borel transform. We also prove that the...

Résurgence paramétrique et exponentielle petitesse de l'écart des séparatrices du pendule rapidement forcé

David Sauzin (1995)

Annales de l'institut Fourier

Henri Poincaré avait déjà remarqué que les variétés stable et instable du pendule perturbé, défini par l’hamiltonien H ( q , p , t ) = p 2 / 2 + ( - 1 + cos q ) ( 1 - μ sin ( t / ϵ ) ) , ne coïncident pas lorsque que le paramètre μ n’est pas nul, mais qu’on peut leur associer un même développement formel divergent en puissance de ϵ . Cette divergence est ici analysée au moyen de la récente théorie de la résurgence, et du calcul étranger qui permet de trouver un équivalent asymptotique de l’écart des deux variétés pour ϵ tendant vers zéro - du moins cela est-il montré...

Sequences of 0's and 1's

Grahame Bennett, Johann Boos, Toivo Leiger (2002)

Studia Mathematica

We investigate the extent to which sequence spaces are determined by the sequences of 0's and 1's that they contain.

Sequences of 0's and 1's: sequence spaces with the separable Hahn property

Maria Zeltser (2007)

Studia Mathematica

In [3] it was discovered that one of the main results in [1] (Theorem 5.2), applied to three spaces, contains a nontrivial gap in the argument, but neither the gap was closed nor a counterexample was provided. In [4] the authors verified that all three above mentioned applications of the theorem are true and stated a problem concerning the topological structure of one of these three spaces. In this paper we answer the problem and give a counterexample to the theorem in doubt. Also we establish a...

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