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/