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