Thanks a lot to all of you for your help. It took some time for me to realize that the only difference between Vene and Wadler is in fact, that Wadler has an explicit representation for the fixpoints - which answers the question of existence.
I will spend some more time on digesting all the information :-) and will try to find some information about algebraic compacity. Greetings ben _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
