Two postings here: a question about H-derivations and a question about coalgebras.....DMD __________________________________________ From: "Jianzhong Pan" Subject: question about H-derivation and its dual Date: Sat, 12 Feb 2000 10:14:52 CST I have one question to ask for your help. Given two H-spaces and a map between them one has an obstruction for the map to be an H-map which is called H-derivation. >From reference I learned that Arkowitz(in a lecture Note in Arhus) computed the H-derivation of a map from an H-spaces to another H-space which is the homotopy pullback under certain condition. One of my question is : Is there any other easily accessible published reference for this kind result? Another is : Is there any published dual result? By dual I mean that H-space is replaced by co-H-space and pullback by pushout. I just want to find a reference. Thanks for any help best wishes Pan Jianzhong ______________________________________________________ Date: Sat, 12 Feb 2000 12:23:31 -0500 (EST) From: James Stasheff Subject: question about coalgebras 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 gorund 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