Electron. J. Diff. Eqns., Vol. 2006(2006), No. 85, pp. 1-22.

A topology on inequalities

Anna Maria D'Aristotile, Alberto Fiorenza

Abstract:
We consider sets of inequalities in Real Analysis and construct a topology such that inequalities usually called "limit cases" of certain sequences of inequalities are in fact limits - in the precise topological sense - of such sequences. To show the generality of the results, several examples are given for the notions introduced, and three main examples are considered: Sequences of inequalities relating real numbers, sequences of classical Hardy's inequalities, and sequences of embedding inequalities for fractional Sobolev spaces. All examples are considered along with their limit cases, and it is shown how they can be considered as sequences of one "big" space of inequalities. As a byproduct, we show how an abstract process to derive inequalities among homogeneous operators can be a tool for proving inequalities. Finally, we give some tools to compute limits of sequences of inequalities in the topology introduced, and we exhibit new applications.

Submitted July 12, 2006. Published August 2, 2006.
Math Subject Classifications: 46E99, 54C30, 54A20, 54B15.
Key Words: Real analysis; topology; inequalities; homogeneous operators; Banach spaces; Orlicz spaces; Sobolev spaces; norms; density.

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Anna Maria D'Aristotile
Dipartimento di Costruzioni e Metodi Matematici in Architettura
Universitá di Napoli "Federico II"
via Monteoliveto 3, 80134 Napoli, Italy
email: daristot@unina.it
Alberto Fiorenza
Dipartimento di Costruzioni e Metodi Matematici in Architettura
Universitá di Napoli "Federico II"
via Monteoliveto 3, 80134 Napoli, Italy
and Istituto per le Applicazioni del Calcolo "Mauro Picone"
Consiglio Nazionale delle Ricerche
via Pietro Castellino 111, 80131 Napoli, Italy
email: fiorenza@unina.it

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