Browsing by Author "cfb83f16-4456-4d84-89a3-a0ea3f6f1689"

Now showing items 1-20 of 41

    • openAccess   A Generalized Mazur-Ulam Theorem for Fuzzy Normed Spaces 

      Font, Juan J.; Galindo, Jorge; Macario, Sergio; Sanchis López, Manuel Hindawi Publishing Corporation (2014-06-02)
      We introduce fuzzy norm-preserving maps, which generalize the concept of fuzzy isometry. Based on the ideas from Vogt, 1973, and V¨ais¨al¨a, 2003, we provide the following generalized version of theMazur-Ulam theorem in ...

    • openAccess   A version of the Stone-Weierstrass theorem in fuzzy analysis 

      Font, Juan J.; Sanchis, Delia; Sanchis López, Manuel International Scientific Research Publications (ISRP) (2017-08)
      Let C ( K , E 1 ) be the space of continuous functions defined between a compact Hausdorff space K and the space of fuzzy numbers E 1 endowed with the supremum metric. We provide a set of sufficient conditions ...

    • openAccess   Assessment of facial harmony among Caucasian Spaniards 18 to 60 years of age and its relationship with the golden ratio 

      Ballester Ferrandis, José Francisco; Martínez Soriano, Francisco; Ribera Vega, María Isabel; Font, Juan J. Springer (2018-04)
      Background Throughout history, the perception and defini- tion of beauty and attractiveness have changed and have been influenced by cultural norms. This article analyzes the concept of B facial normality ^ (faces ...

    • openAccess   Best Approximation Results for Fuzzy-Number-Valued Continuous Functions 

      Font, Juan J.; Macario, Sergio MDPI (2023-02)
      In this paper, we study the best approximation of a fixed fuzzy-number-valued continuous function to a subset of fuzzy-number-valued continuous functions. We also introduce a method to measure the distance between a ...

    • openAccess   Bilinear isometries on spaces of vector-valued continuous functions 

      Font, Juan J.; Sanchis López, Manuel Elsevier (2012)
      Let X, Y, Z be compact Hausdorff spaces and let E1, E2, E3 be Banach spaces. If T:C(X,E1)×C(Y,E2)→C(Z,E3) is a bilinear isometry which is stable on constants and E3 is strictly convex, then there exist a nonempty subset ...

    • openAccess   Bilinear isometries on subspaces of continuous functions 

      Font, Juan J.; Sanchis López, Manuel Wiley-VCH Verlag (2010-03-18)
      Let A and B be strongly separating linear subspaces of C0(X) and C0(Y ), respectively, and assume that ∂A ̸= ∅ (∂A stands for the set of generalized peak points for A) and ∂B ≠ ∅. Let T : A×B −→ C0(Z) be a bilinear isometry. ...

    • openAccess   Cálculo 

      Font, Juan J.; Hernández, Salvador; Macario, Sergio Universitat Jaume I (2009)

    • openAccess   Completeness, metrizability and compactness in spaces of fuzzy-number-valued functions 

      Font, Juan J.; Sanchis, Delia; Sanchis López, Manuel Elsevier (2018-05-15)
      Fuzzy-number-valued functions, that is, functions defined on a topological space taking values in the space of fuzzy numbers, play a central role in the development of Fuzzy Analysis. In this paper we study completeness, ...

    • openAccess   Constructive approximation of continuous interval- valued functions 

      Font, Juan J.; Macario, Sergio Taylor & Francis (2021-11-28)
      In this paper we present a Stone-Weierstrass type result in the context of continuous interval-valued functions defined on a compact Hausdorff space. We also provide a Jackson type approximation result involving the modulus ...

    • openAccess   Constructive approximation of level continuous fuzzy functions 1 

      Font, Juan J.; Sanchis, Delia; Sanchis López, Manuel IOS (2019-06)
      We consider the space of continuous functions defined between a locally compact Hausdorff space and the space of fuzzy numbers endowed with the level convergence topology. We obtain a Stone-Weierstrass type theorem for ...

    • openAccess   Diameter preserving mappings between function algebras 

      Font, Juan J.; Hosseini, Maliheh Mathematical Society of the Republic of China (2011)
      In this paper we study the behaviour of linear diameter preserving mappings when defined between subalgebras of continuous functions. Namely, we obtain a representation of such mappings as the sum of a weighted composition ...

    • openAccess   Diameter preserving maps on function spaces 

      Hosseini, Maliheh; Font, Juan J. Springer (2016-08-16)
      In this paper we describe, under certain assumptions, surjective diameter preserving mappings when defined between function spaces, not necessarily algebras, thus extending most of the previous results for these operators. ...

    • openAccess   Disjointness preserving mappings on BSE Ditkin algebras 

      Font, Juan J. Institute of Mathematics, University of Debrecen, Hungary (2011)
      Let A and B be regular Banach function algebras. A linear map T de_ned from A into B is said to be disjointness preserving or sepa- rating if f _ g _ 0 implies T(f) _ T(g) _ 0 for all f; g 2 A. We prove that if there ...

    • openAccess   Disjointness preserving maps between vector-valued group algebras 

      Hosseini, Maliheh; Font, Juan J. (2018-06)
      Let G be a locally compact abelian group and B be a commutative Banach algebra. Let L1(G,B) be the Banach algebra of B-valued Bochner integrable functions on G. In this paper we provide a complete description of continuous ...

    • openAccess   Endograph Metric and a Version of the Arzelà–Ascoli Theorem for Fuzzy Sets 

      Font, Juan J.; Macario, Sergio; Sanchis, Manuel MDPI (2023)
      In this paper, we provide several Arzelà–Ascoli-type results on the space of all continuous functions from a Tychonoff space X into the fuzzy sets of Rn , (FUSCB(Rn),Hend) , which are upper semi-continuous and have bounded ...

    • openAccess   Finite codimensional isometries on spaces of vector-valued continuous functions 

      Araujo Gómez, Jesús; Font, Juan J. Elsevier (2015-01)
      Based on the vector-valued generalization of Holsztyński's theorem by M. Cambern, we provide a complete description of the linear isometries of C(X,E)C(X,E) into C(Y,F)C(Y,F) whose range has finite codimension.

    • openAccess   Isometries on spaces of absolutely continuous functions in a noncompact framework 

      Hosseini, Maliheh; Font, Juan J. Elsevier (2020-02-19)
      In this paper we deal with surjective linear isometries between spaces of scalar-valued absolutely continuous functions on arbitrary (not necessarily closed or bounded) subsets of the real line (with at least two points). ...

    • openAccess   Korovkin-Type Results on Convergence of Sequences of Positive Linear Maps on Function Spaces 

      Hosseini, Maliheh; Font, Juan J. Springer Verlag (2019-11-11)
      In this paper, we deal with the convergence of sequences of positive linear maps to a (not assumed to be linear) isometry on spaces of continuous functions. We obtain generalizations of known Korovkin-type results and ...

    • openAccess   Linear and Multilinear Isometries in a Noncompact Framework 

      Hosseini, Maliheh; Font, Juan J. Springer (2021-03-19)
      Both classical linear and multilinear isometries defined between subalgebras of bounded continuous functions on (complete) metric spaces are studied. Particularly, we prove that certain such subalgebras, including the ...

    • closedAccess   Local and 2-local isometries between absolutely continuous function spaces 

      Hosseini, Maliheh; Font, Juan J. Element d.o.o. (2021-12-01)
      In this paper we give a complete description of local and 2-local isometries defined between spaces of scalar-valued absolutely continuous functions on arbitrary (not necessarily compact) subsets of the real line with at ...