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