A necessary and sufficient condition is given for a rearrangement invariant function space to contain a complemented isomorphic copy of l1(l2).
@article{urn:eudml:doc:42131, title = {On complemented subspaces of rearrangement invariant function spaces.}, journal = {Collectanea Mathematica}, volume = {44}, year = {1993}, pages = {247-260}, zbl = {0815.46028}, mrnumber = {MR1280742}, language = {en}, url = {http://dml.mathdoc.fr/item/urn:eudml:doc:42131} }
Raynaud, Yves. On complemented subspaces of rearrangement invariant function spaces.. Collectanea Mathematica, Tome 44 (1993) pp. 247-260. http://gdmltest.u-ga.fr/item/urn:eudml:doc:42131/