Dear All, I had posted the message below yesterday, but the message had some html in it (from previous messages in the exchange, I believe). It is somewhat redundant today because Professor Porst's paper has now been mentioned in a different posting, but it can still serve as a note of appreciation to him. :-) Best regards, Todd ----- Original Message ----- From: Todd Trimble To: Hans-E. Porst Cc: Bisson, Terrence P ; Categories list Sent: Thursday, August 25, 2011 11:49 AM Subject: Re: categories: Re: a coalgebras over fields question. Indeed, Hans-E. Porst has done a lot of valuable work in the area of coalgebras and comodules. I would also recommend his article "On corings and comodules", Archivum Mathematicum 42 (2006), no. 4, 419-425. Todd [For admin and other information see: http://www.mta.ca/~cat-dist/ ]