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An example in the theory of approximate systems

Nikica Uglešić (1993)

Commentationes Mathematicae Universitatis Carolinae

An approximate inverse sequence of plane continua is constructed which negatively answers a question of S. Mardeši’c related to approximate and usual inverse systems. The example also shows that an important result of M.G. Charalambous cannot be improved. As an application, it is shown that a procedure of making an approximate inverse sequence commutative (“taming”) is discontinuous.

Analyse de récession et résultats de stabilité d’une convergence variationnelle, application à la théorie de la dualité en programmation mathématique

Driss Mentagui (2003)

ESAIM: Control, Optimisation and Calculus of Variations

Soit X un espace de Banach de dual topologique X ' . 𝒞 X (resp. 𝒞 X ' ) désigne l’ensemble des parties non vides convexes fermées de X (resp. w * -fermées de X ' ) muni de la topologie de la convergence uniforme sur les bornés des fonctions distances. Cette topologie se réduit à celle de la métrique de Hausdorff sur les convexes fermés bornés [16] et admet en général une représentation en terme de cette dernière [11]. De plus, la métrique qui lui est associée s’est révélée très adéquate pour l’étude quantitative...

Analyse de récession et résultats de stabilité d'une convergence variationnelle, application à la théorie de la dualité en programmation mathématique

Driss Mentagui (2010)

ESAIM: Control, Optimisation and Calculus of Variations

Let X be a Banach space and X' its continuous dual. C(X) (resp. C(X')) denotes the set of nonempty convex closed subsets of X (resp. ω*-closed subsets of X') endowed with the topology of uniform convergence of distance functions on bounded sets. This topology reduces to the Hausdorff metric topology on the closed and bounded convex sets [16] and in general has a Hausdorff-like presentation [11]. Moreover, this topology is well suited for estimations and constructive approximations [6-9]. We...

Approximate inverse systems of uniform spaces and an application of inverse systems

Michael G. Charalambous (1991)

Commentationes Mathematicae Universitatis Carolinae

The fundamental properties of approximate inverse systems of uniform spaces are established. The limit space of an approximate inverse sequence of complete metric spaces is the limit of an inverse sequence of some of these spaces. This has an application to the dimension of the limit space of an approximate inverse system. A topologically complete space with dim n is the limit of an approximate inverse system of metric polyhedra of dim n . A completely metrizable separable space with dim n is the limit of an...

Approximate quantities, hyperspaces and metric completeness

Valentín Gregori, Salvador Romaguera (2000)

Bollettino dell'Unione Matematica Italiana

Mostriamo che se X , d è uno spazio metrico completo, allora è completa anche la metrica D , indotta in modo naturale da d sul sottospazio degli insiemi sfocati («fuzzy») di X dati dalle quantità approssimate. Come è ben noto, D è una metrica molto interessante nella teoria dei punti fissi di applicazioni sfocate, poiché permette di ottenere risultati soddisfacenti in questo contesto.

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