Fourier Series defined in a Hilbert Space of Fuzzy Numbers
DOI:
https://doi.org/10.5540/03.2026.012.01.0290Palavras-chave:
Space of Square Summable Real Sequences, Strong Linear Independence, Hilbert Space of Fuzzy Numbers, Fuzzy Fourier SeriesResumo
This study conducts an introductory investigation of the Fourier series with fuzzy coefficients. A structure of Hilbert space is provided throughout an identification of the convergent square summable real sequences into a set generated by an enumerable family of strongly linearly independent subsets of fuzzy numbers. An application to a signal processing model with the fuzzy Fourier series approximation of the square wave is presented.
Downloads
Referências
B. Bede. Mathematics of Fuzzy Sets and Fuzzy Logic. Vol. 295. Studies in Fuzziness and Soft Computing. Springer, 2013, pp. 1–258.
E. Bracewell. The Fourier Transform And Its Applications. Vol. 1. wiley New York, 1978.
E. Esmi, F. Barros L. C. Santo-Pedro, and B. Laiate. “Banach spaces generated by strongly linearly independent fuzzy numbers”. In: Fuzzy Sets and Systems 417 (2021), pp. 110–129.
E. Esmi, B. Laiate, F. Santo-Pedro, and L. C. Barros. “Calculus for fuzzy functions with strongly linearly independent fuzzy coefficients”. In: Fuzzy Sets and Systems 436 (2022), pp. 1–31.
E. Esmi, F. Santo-Pedro, L. C. Barros, and W. Lodwick. “Fréchet derivative for linearly correlated fuzzy function”. In: Information Sciences 435 (2018), pp. 150–160.
D. G. Figueiredo. Análise de Fourier e equações diferenciais parciais. Instituto de Matemática Pura e Aplicada, CNPq, 1987.
W. E. John, D. Bateman, S. Hauberg, and R. Wehbring. GNU Octave version 9.2.0 manual: a high-level interactive language for numerical computations. 2025. url: https://www.gnu.org/software/octave/doc/v9.2.0/.
U. Kadak and F. Başar. “On Fourier Series of Fuzzy-Valued Functions”. In: The Scientific World Journal 2014.1 (2014), p. 782652.
E. Kreyszig. Introductory Functional Analysis with Applications. Wiley Classics Li brary. Wiley, 1989.
B. Laiate. “Fuzzy Calculus in Banach Spaces of Fuzzy Numbers: Theory and Applications”. PhD thesis. Campinas University, 2022.
B. Laiate and A. M. A. Bertone. “Infinite Dimensional Banach and Hilbert Spaces of Fuzzy Numbers”. In: Submited for publication. (2025).
R. J. Marks. Handbook of Fourier Analysis & Its Applications. Oxford University Press, 2009.
W. Rudin. Real and Complex Analysis. New York, NY: McGraw-Hill, 1974.