000136213 001__ 136213 000136213 005__ 20240719195438.0 000136213 0247_ $$2doi$$a10.3390/sym16060738 000136213 0248_ $$2sideral$$a139112 000136213 037__ $$aART-2024-139112 000136213 041__ $$aeng 000136213 100__ $$0(orcid)0000-0003-4847-0493$$aNavascués, María A. 000136213 245__ $$aNonexpansiveness and Fractal Maps in Hilbert Spaces 000136213 260__ $$c2024 000136213 5060_ $$aAccess copy available to the general public$$fUnrestricted 000136213 5203_ $$aPicard iteration is on the basis of a great number of numerical methods and applications of mathematics. However, it has been known since the 1950s that this method of fixed-point approximation may not converge in the case of nonexpansive mappings. In this paper, an extension of the concept of nonexpansiveness is presented in the first place. Unlike the classical case, the new maps may be discontinuous, adding an element of generality to the model. Some properties of the set of fixed points of the new maps are studied. Afterwards, two iterative methods of fixed-point approximation are analyzed, in the frameworks of b-metric and Hilbert spaces. In the latter case, it is proved that the symmetrically averaged iterative procedures perform well in the sense of convergence with the least number of operations at each step. As an application, the second part of the article is devoted to the study of fractal mappings on Hilbert spaces defined by means of nonexpansive operators. The paper considers fractal mappings coming from φ-contractions as well. In particular, the new operators are useful for the definition of an extension of the concept of α-fractal function, enlarging its scope to more abstract spaces and procedures. The fractal maps studied here have quasi-symmetry, in the sense that their graphs are composed of transformed copies of itself. 000136213 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/ 000136213 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000136213 773__ $$g16, 6 (2024), 19 pp.$$pSymmetry (Basel)$$tSymmetry$$x2073-8994 000136213 8564_ $$s805881$$uhttps://zaguan.unizar.es/record/136213/files/texto_completo.pdf$$yVersión publicada 000136213 8564_ $$s2344109$$uhttps://zaguan.unizar.es/record/136213/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000136213 909CO $$ooai:zaguan.unizar.es:136213$$particulos$$pdriver 000136213 951__ $$a2024-07-19-18:29:26 000136213 980__ $$aARTICLE