Abstract
In this paper, we extend the saturation results for the sampling Kantorovich operators proved in a previous paper, to more general settings. In particular, exploiting certain Voronovskaja-formulas for the well-known generalized sampling series, we are able to extend a previous result from the space of \(C^2\)-functions to the space of \(C^1\)-functions. Further, requiring an additional assumption, we are able to reach a saturation result even in the space of the uniformly continuous and bounded functions. In both the above cases, the assumptions required on the kernels, which define the sampling Kantorovich operators, have been weakened with respect to those assumed previously. On this respect, some examples have been discussed at the end of the paper.
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Acknowledgements
The authors are members of the Gruppo Nazionale per l’Analisi Matematica, la Probabilitá e le loro Applicazioni (GNAMPA) of the Istituto Nazionale di Alta Matematica (INdAM). The authors are partially supported by the “Department of Mathematics and Computer Science” of the University of Perugia (Italy). Moreover, the second author of the paper has been partially supported within the 2017 GNAMPA-INdAM Project “Approssimazione con operatori discreti e problemi di minimo per funzionali del calcolo delle variazioni con applicazioni all’imaging”.
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Communicated by Uwe Kaehler.
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Bartoccini, B., Costarelli, D. & Vinti, G. Extension of Saturation Theorems for the Sampling Kantorovich Operators. Complex Anal. Oper. Theory 13, 1161–1175 (2019). https://doi.org/10.1007/s11785-018-0852-z
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DOI: https://doi.org/10.1007/s11785-018-0852-z
Keywords
- Inverse results
- Sampling Kantorovich series
- Order of approximation
- Generalized sampling operators
- Saturation order