Functorial approach structures

• Brümmer, Guillaume C.L. ^[1] ; Sioen, Mark ^[2]
  1. [1] University of Cape Town

     University of Cape Town

     City of Cape Town, Sudáfrica

     
  2. [2] Free University of Brussels
• Localización: Applied general topology, ISSN-e 1989-4147, ISSN 1576-9402, Vol. 4, Nº. 1, 2003, págs. 91-97
• Idioma: inglés
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• Resumen

  • We show that there exists at least a proper class of functorial approach structures, i.e., right inverses to the forgetful functor T : AP→ Top (where AP denotes the topological construct of approach spaces and contractions as introduced by R. Lowen). There is however a great difference in nature of these functorial approach structures when compared to the quasi-uniform paradigm which has been extensively studied by the first author: whereas it is well-known from [2] that a large class of epireflective subcategories of Top0 can be “parametrized” using the interaction of functorial quasi-uniformities with the quasi-uniform bicompletion, we show that using functorial approach structures together with the approach bicompletion developed in [10], only Top0 itself can be retrieved in this way.