Dan Piponi wrote: > Derek Elkins wrote: > >> Yes, I have the same problem...Basically, I'm >> pretty sure the construction of that free theorem doesn't rely on any >> of the actual details... > > For a long time I've thought such a higher order free theorem must > exist, and I've mentioned it to a few people, and searched hard for a > paper on it, but I haven't seen an actual statement and proof. > >> At this point, though, I haven't put >> much effort into proving that the free theorem holds uniformly > > Well I encourage you to as I've a hunch the correctly generalised > theorem will be quite pretty. I'd have a go but the style of proof for > these sorts of things is outside of my domain of > confidence/experience.
This looks relevant: Janis Voigtländer. Free Theorems Involving Type Constructor Classes. http://wwwtcs.inf.tu-dresden.de/~voigt/icfp09.pdf Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe