I have mixed feelings about Module.T, but consider it useful. basically, I use it only when the module naturally only exports a single type which is the purpose of the module (modules which incidentally only export a single type but have a different focus shouldn't use the type synonym) and the modules functions are named in such a way that it is intended to be used in a qualified way. (like the new Data.Map and Data.Set). However, I don't try to force any modules or types into this model if they don't naturally fall into them. I also make sure that the T is a type synonym for the actual name. as in module Vector where data Vector = ... type T = Vector This ensures that tools that strip the module name still give reasonable names to things since most expand type synonyms away. So, in conclusion, I think Vector and Matrix do naturally fall into these conditions so should have T but as type synonyms and not the base name. John -- John Meacham - ⑆repetae.net⑆john⑈