Geodesic
Hausdorff Fréchet closure spaces with maximum topological defect
Bollettino della Unione matematica italiana, Série 8, 5B (2002) no. 3, pp. 641-665.

Voir la notice de l'article provenant de la source Biblioteca Digitale Italiana di Matematica

It is well-known that the topological defect of every Fréchet closure space is less than or equal to the first uncountable ordinal number $\omega_{1}$. In the case of Hausdorff Fréchet closure spaces we obtain some general conditions sufficient so that the topological defect is exactly $\omega_{1}$. Some classical and recent results are deduced from our criterion.
È noto che il difetto topologico di ogni spazio di chiusura di Fréchet é minore o uguale al primo ordinale non numerabile $\omega_{1}$. Nel caso di spazi di chiusura di Hausdorff Fréchet si ottengono alcune condizioni generali sufficienti affinché il difetto topologico sia pari a $\omega_{1}$. Alcuni risultati classici e recenti sono dedotti dal nostro criterio. 
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Ghiloni, Riccardo. Hausdorff Fréchet closure spaces with maximum topological defect. Bollettino della Unione matematica italiana, Série 8, 5B (2002) no. 3, pp. 641-665. http://geodesic.mathdoc.fr/item/BUMI_2002_8_5B_3_a4/

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