As of some notes from 1996, it was an open question as
to how to make a closed model category from coalgebras
which as dg modules are flat over the ground ring
one problem: the naive cokernel is no longer flat
.oooO Jim Stasheff jds@math.unc.edu
(UNC) Math-UNC (919)-962-9607
\ ( Chapel Hill NC FAX:(919)-962-2568
\*) 27599-3250
http://www.math.unc.edu/Faculty/jds