We describe how the Szlenk index has been used in various areas of the geometry of Banach spaces. We cover the following domains of application of this notion: non existence of universal spaces, linear classification of C(K) spaces, descriptive set theory, renorming problems and non linear classification of Banach spaces.
In the context of the theory of infinite matrices and linear operators, two articles by Peano and by Gramegna on systems of linear differential equations have interesting implications for the reconstruction of research on functional analysis between 1887 and 1910. With the aim of evaluating their historical value, linked to logic and vector calculus, this paper provides a detailed analysis of their treatment, demonstrating the modernity of the analytic tools used. In this paper we also reveal the...
We present here some evidence of the activity of Banach Lwów School of functional analysis in the field of topological algebras. We shall list several results connected with such names as Stanisław Mazur (1905-1981), Maks (Meier) Eidelheit (1910-1943), Stefan Banach (1892-1945) and Andrzej Turowicz (1904-1989) showing that if the war had not interrupted this activity we could expect more interesting results in this direction.
Článek je věnován genezi pojmu kompaktního operátoru. Cesta k jeho vytvoření trvala několik desetiletí a nebyla přímočará. Od problémů fyziky k jejich matematické formulaci pomocí integrálních rovnic, přes okrajové úlohy teorie potenciálu, přes snahy o řešení nekonečných soustav lineárních rovnic. Cesta ilustruje ideu přechodu od konečného k nekonečnému, od diskrétního ke spojitému. Ukazuje, proč a jak matematika dospěla k funkcím nekonečně mnoha proměnných, k prostorům funkcí a obecněji, k nekonečněrozměrným...
Cet article examine comment la notion d’espace vectoriel de fonctions s’est peu à peu imposée dans l’analyse entre 1880 et 1930 environ. Malgré certaines approches formelles précoces, les questions linéaires en dimension infinie sont longtemps restées marquées par l’analogie avec la dimension finie, que l’on traitait alors à l’aide des déterminants. Nous regardons comment l’étude de l’équation de Fredholm d’une part, en particulier le travail de Hilbert, et l’émergence de notions topologiques d’autre...
As written in L. Schwartz' book, Heaviside's theory of cables is an important source of the theory of generalized functions. The partial differential equations he discussed were the usual heat equation and the simplest hyperbolic equations of one space dimension, but he had to solve them as evolution equations in the unusual direction of the distance along which the electric signals propagate. Although he obtained explicit expressions of solutions, which were of great economical values, it has not...
The paper the title refers to is that in Proceedings of the Edinburgh Mathematical Society, 40 (1997), 367-374. Taking it as an excuse we intend to realize a twofold purpose: 1° to atomize that important result showing by the way connections which are out of favour, 2° to rectify a tiny piece of history. The objective 1° is going to be achieved by adopting means adequate to goals; it is of great gravity and this is just Mathematics. The other, 2°, comes...