The -fold product of an arbitrary space usually supports only the obvious
permutation action of the symmetric group . However, if is a -complete,
homotopy associative, homotopy commutative -space one can define a homotopy action of
on . In various cases, e.g. if multiplication by is
null homotopic then we get a homotopy action of for some .
After one suspension this allows one to split using idempotents of which can be lifted to . In fact
all of this is possible if is an -space...