On construit un simplexe de Choquet dont l’ensemble des points extrémaux est -analytique, mais n’est pas -Borélien. L’ensemble est un dans sa compactification de Stone-Cech. C’est donc un exemple d’ensemble qui n’est pas absolu.
We construct a Choquet simplex whose set of extreme points is -analytic, but is not a -Borel set. The set has the surprising property of being a set in its Stone-Cech compactification. It is hence an example of a set that is not absolute.
@article{AIF_1985__35_3_195_0, author = {Talagrand, Michel}, title = {Choquet simplexes whose set of extreme points is $K$-analytic}, journal = {Annales de l'Institut Fourier}, volume = {35}, year = {1985}, pages = {195-206}, doi = {10.5802/aif.1024}, mrnumber = {87a:46022}, zbl = {0564.46008}, language = {en}, url = {http://dml.mathdoc.fr/item/AIF_1985__35_3_195_0} }
Talagrand, Michel. Choquet simplexes whose set of extreme points is $K$-analytic. Annales de l'Institut Fourier, Tome 35 (1985) pp. 195-206. doi : 10.5802/aif.1024. http://gdmltest.u-ga.fr/item/AIF_1985__35_3_195_0/
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