Abstract In this paper we establish some bounds for the (Φ, f)-mean difference introduced in the general settings of measurable spaces and Lebesgue integral, which is a two functions generalization of Gini mean difference that has been widely used by economists and sociologists to measure economic inequality.

Resumen En este artículo establecemos algunas cotas para la (Φ, f)-diferencia media introducida en el contexto general de espacios medibles e integral de Lebesgue, que es una generalización a dos funciones de la diferencia media de Gini que ha sido ampliamente utilizada por economistas y sociólogos para medir desigualdad económica.

Resumen En esta investigación se caracteriza la r-nuclearidad de operadores integrales de Fourier en espacios de Lebesgue. Las nociones de traza nuclear y operador nuclear sobre espacios de Banach son conceptos análogos a aquellas de traza espectral y de operador de clase traza en espacios de Hilbert. Operadores integrales de Fourier, por otro lado, surgen para expresar soluciones a problemas de Cauchy hiperbólicos o para estudiar la función espectral asociada a un operador geométrico sobre una variedad diferenciable. Los operadores integrales de Fourier se consideran actuando sobre ℝn, el grupo discreto ℤn, el toro de dimensión n y finalmente, espacios simétricos (variedades compactas homogéneas). Se presentan ejemplos explícitos de tales caracterizaciones sobre ℤn, el grupo especial unitario SU(2), y el plano complejo proyectivo ℂℙ2. Los resultados principales de la presente investigación se aplican en la caracterización de operadores pseudo diferenciales nucleares definidos mediante el proceso de cuantificación de Weyl.

Abstract In this paper we characterise the r-nuclearity of Fourier integral operators on Lebesgue spaces. Fourier integral operators will be considered in ℝn, the discrete group ℤn, the n-dimensional torus and symmetric spaces (compact homogeneous manifolds). We also give formulae for the nuclear trace of these operators. Explicit examples will be given on ℤn, the torus 𝕋n, the special unitary group SU(2), and the projective complex plane ℂℙ2. Our main theorems will be applied to the characterization of r-nuclear pseudo-differential operators defined by the Weyl quantization procedure. MSC2010: 58J40; 47B10, 47G30, 35S30.

Resumen En esta nota anunciamos los resultados de nuestra investigación sobre las propiedades L p de operadores pseudodiferenciales multilineales periódicos y/o discretos. Primero, revisaremos el análisis multilineal de tales operadores mostrando versiones análogas de los teoremas clásicos disponibles en el análisis multilineal euclidiano (debidos a Coifman y Meyer, Tomita, Miyachi, Fujita, Grafakos, Tao, etc.), pero, en el contexto de operadores periódicos y/o discretos. Se caracterizará la s-nuclearidad, 0 < s ≤ 1, para operadores multilineales pseudodiferenciales periódicos y/o discretos. Para cumplir este objetivo se clasificarán aquellos operadores lineales s-nucleares, 0 < s ≤ 1, multilineales con núcleo, sobre espacios de Lebesgue arbitrarios definidos en espacios de medida σ-finitos. Finalmente, como aplicación de los resultados presentados se obtiene la versión periódica de la desigualdad de Kato-Ponce, y se examina la s-nuclearidad de potenciales de Bessel lineales y multilineales, como también la s-nuclearidad de operadores integrales de Fourier periódicos admitiendo símbolos con tipos adecuados de singularidad.

Abstract In this note we announce our investigation on the L p properties for periodic and discrete multilinear pseudo-differential operators. First, we review the periodic analysis of multilinear pseudo-differential operators by showing classical multilinear Fourier multipliers theorems (proved by Coifman and Meyer, Tomita, Miyachi, Fujita, Grafakos, Tao, etc.) in the context of periodic and discrete multilinear pseudo-differential operators. For this, we use the periodic analysis of pseudo-differential operators developed by Ruzhansky and Turunen. The s-nuclearity, 0 < s ≤ 1, for the discrete and periodic multilinear pseudo-differential operators will be investigated. To do so, we classify those s-nuclear, 0 < s ≤ 1, multilinear integral operators on arbitrary Lebesgue spaces defined on σ-finite measures spaces. Finally, we present some applications of our analysis to deduce the periodic Kato-Ponce inequality and to examine the s-nuclearity of multilinear Bessel potentials as well as the s-nuclearity of periodic Fourier integral operators admitting suitable types of singularities. MSC2010: 58J40, 47B10, 47G30, 35S30.

Resumen Se optimiza la desigualdad inversa de Jensen para funciones convexas en términos de diferencias divididas vía un refinamiento. Se proveen aplicaciones de la desigualdad de Hölder para medias y para medidas f-divergentes en teoría de la información.

Abstract A refinement and a new sharp reverse of Jensen's inequality for convex functions in terms of divided diferences is obtained. Applications for means, the Hölder inequality and for f-divergence measures in information theory are also provided.

As redes de Petri (RPs) constituem-se em uma ferramenta matemática e gráfica de uso geral. Sugere-se, neste trabalho, o uso de RPs como uma ferramenta de modelagem voltada para o ensino de noções matemáticas. A modelagem apoia-se no fato de as RPs terem como característica a representação de sistemas que utilizam forte base matemática. Como estudo de caso, apresenta-se uma modelagem para a organização do conteúdo de ensino sobre integrabilidade de funções reais baseada na evolução do conceito de integral. Para isto, considera-se uma função limitada, definida em um intervalo fechado e limitado da reta, que é analisada relativamente a condições que garantam ou excluam a sua integrabilidade por Cauchy, por Riemann, por Lebesgue ou por nenhum destes. A ideia de se modelar este conceito por RPs originou-se no contexto da sala de aula, por ocasião de seu ensino a alunos de primeiro ano de engenharia.

Petri Nets (PNs) are a mathematical and graphical tool for general use. In this paper, the use of PNs is promoted as a modeling tool to organize the teaching of mathematical notions. The modeling presented in this work relies on the strong mathematical basis of PNs. As a case study, a model is constructed for teaching integrability of real functions, based on the evolution of the integral concept. With this aim, it is considered a real bounded function, defined on a closed and bounded interval, that is analyzed according to conditions which ensure or exclude its integration by Cauchy, by Riemann, by Lebesgue or by none of these integrals. The idea of modeling integrals using PN was originated in the context of mathematical classes, as the integral was being taught to first year engineering students.

We show that if f is lying on the intersection of the space of Henstock-Kurzweil integrable functions and the space of the bounded variation functions in the neighborhood of ±8, then its Fourier Transform exists in all R. This result is more general than the classical result which enunciates that if f is Lebesgue integrable, then the Fourier Transform of f exists in all R, because we also have proved that there are functions which belong to the intersection of the space of the Henstock-Kurzweil integrable functions and the space of the bounded variation functions which are not Lebesgue integrable.