arXiv subjects

Sergio Macario

Publications and source records attributed to Sergio Macario.

6 recordsLinked to original sources

arXiv2025

Best approximation results for fuzzy-number-valued continuous functions

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 fuzzy-number-valued continuous function and a real-valued one. Then we prove the existence of the best approximation of a fuzzy-number-valued continuous function to the space of real-valued continuous functions by using the well-known Michael Selection Theorem.

math.GM↗

arXiv2025

Neural Network Operators on fuzzy number valued continuous functions

We extend Cardaliaguet-Euvrard neural network operators to the context of fuzzy number valued continuous functions and study their behaviour. We focus on level continuous, sendograph continuous and endograph continuous functions and obtain Jackson-type results in all these cases.

math.GM↗

arXiv2025

Gromov-Hausdorff compactness theorem for non-Archimedean Fuzzy Metric Spaces

The authors introduced in a previous paper the notion of fuzzy Gromov-Hausdorff distance between non-Archimedean compact fuzzy metric spaces, presenting a fuzzy version of the Gromov's completeness theorem. In this paper we present a fuzzy version of the Gromov's precompactness theorem which allows to deduce the classical theorem for compact metric spaces by means of the standard fuzzy metric associated to a metric space. This completes the previous work.

math.GN↗

arXiv2025

Jackson-type approximation for fuzzy-valued functions by means of trapezoidal functions

In this paper we provide new several Jackson-type approximations results for continuous fuzzy-number-valued functions which improve several previous ones. We use alternative techniques adapted from Interval Analysis which rely on the gH-difference (which might not exist) and the generalized difference (which might lack the cancellation law ) of fuzzy numbers.

math.GM↗

arXiv2024

Constructive approximation of continuous interval-valued functions

In this paper we present a Stone-Weierstrass type result in the context of continuous interval-valued functions defined on a compact Hausdorff space. Namely, we provide a constructive proof of the approximation.

math.FA↗

arXiv2010

Pseudocompact group topologies with no infinite compact subsets

We show that every Abelian group satisfying a mild cardinal inequality admits a pseudocompact group topology from which all countable subgroups inherit the maximal totally bounded topology (we say that such a topology satisfies property $\h$). Every pseudocompact Abelian group $G$ with cardinality $|G|\leq 2^{2^\cc}$ satisfies this inequality and therefore admits a pseudocompact group topology with property $\h$. Under the Singular Cardinal Hypothesis (SCH) this criterion can be combined with an analysis of the algebraic structure of pseudocompact groups to prove that every pseudocompact Abelian group admits a pseudocompact group topology with property $\h$. We also observe that pseudocompact Abelian groups with property $\h$ contain no infinite compact subsets and are examples of Pontryagin reflexive precompact groups that are not compact.

math.GR↗