21 research outputs found

    Abstract Ces\`aro spaces: Integral representations

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    The Ces\`aro function spaces Cesp=[C,Lp]Ces_p=[C,L^p], 1≤p≤∞1\le p\le\infty, have received renewed attention in recent years. Many properties of [C,Lp][C,L^p] are known. Less is known about [C,X][C,X] when the Ces\`aro operator takes its values in a rearrangement invariant (r.i.) space XX other than LpL^p. In this paper we study the spaces [C,X][C,X] via the methods of vector measures and vector integration. These techniques allow us to identify the absolutely continuous part of [C,X][C,X] and the Fatou completion of [C,X][C,X]; to show that [C,X][C,X] is never reflexive and never r.i.; to identify when [C,X][C,X] is weakly sequentially complete, when it is isomorphic to an AL-space, and when it has the Dunford-Pettis property. The same techniques are used to analyze the operator C:[C,X]→XC:[C,X]\to X; it is never compact but, it can be completely continuous.Comment: 21 page

    Fine spectra of the finite Hilbert transform in function spaces

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    We investigate the spectrum and fine spectra of the finite Hilbert transform acting on rearrangement invariant spaces over (−1,1)(-1,1) with non-trivial Boyd indices, thereby extending Widom's results for LpL^p spaces. In the case when these indices coincide, a full description of the spectrum and fine spectra is given.Comment: 26 pages, 1 figure. Minor changes from previous version. This is the final version, to be published in Advances in Mathematic

    A note on function spaces generated by Rademacher series

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    Giovanni Battista Guccia: pioneer of international cooperation in mathematics

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    This book examines the life and work of mathematician Giovanni Battista Guccia, founder of the Circolo Matematico di Palermo and its renowned journal, the Rendiconti del Circolo matematico di Palermo. The authors describe how Guccia, an Italian geometer, was able to establish a mathematical society in Sicily in the late nineteenth century, which by 1914 would grow to become the largest and most international in the world, with one of the most influential journals of the time. The book highlights the challenges faced by Guccia in creating an international society in isolated Palermo, and places Guccia’s activities in the wider European context through comparisons with the formation of the London Mathematical Society and the creation of Mittag-Leffler’s Acta Mathematica in Stockholm. Based on extensive searches in European archives, this scholarly work follows both historical and scientific treads, and will appeal to those interested in the history of mathematics and science in general

    Extensions of the classical Cesaro operator on Hardy spaces

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    For each 1\le p<\infty, the classical Cesàro operator C\mathcal C from the Hardy space HpH^p to itself has the property that there exist analytic functions f∉Hpf\notin H^p with C(f)∈Hp{\mathcal C}(f)\in H^p. This article deals with the identification and properties of the (Banach) space [C,Hp][{\mathcal C}, H^p] consisting of all analytic functions that C\mathcal C maps into HpH^p. It is shown that [C,Hp][{\mathcal C}, H^p] contains classical Banach spaces of analytic functions XX, genuinely bigger that HpH^p, such that C\mathcal C has a continuous HpH^p-valued extension to XX. An important feature is that [C,Hp][{\mathcal C}, H^p] is the largest amongst all such spaces XX
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