We show that if a separable Banach space X contains an isometric copy of every strictly convex separable Banach space, then X contains an isometric copy of l1 equipped with its natural norm. In particular, the class of strictly convex separable Banach spaces has no universal element. This provides a negative answer to a question asked by J. Lindenstrauss.
Probamos que si un espacio separable X contiene una copia isométrica de todo espacio estrictamente convexo separable, entonces X contiene una copia isométrica de l1 con su norma natural. En particular, la clase de los espacios de Banach estrictamente convexos no tiene elemento universal. Esto responde negativamente a una pregunta de J. Lindenstrauss.
@article{urn:eudml:doc:41647, title = {Universal spaces for strictly convex Banach Spaces.}, journal = {RACSAM}, volume = {100}, year = {2006}, pages = {137-146}, mrnumber = {MR2267405}, zbl = {1118.46019}, language = {en}, url = {http://dml.mathdoc.fr/item/urn:eudml:doc:41647} }
Godefroy, Gilles. Universal spaces for strictly convex Banach Spaces.. RACSAM, Tome 100 (2006) pp. 137-146. http://gdmltest.u-ga.fr/item/urn:eudml:doc:41647/