"Galchin, Vasili" wrote:

Hello,

What is the relationship of a Haskell class to universal algebra? (a refresher ... http://en.wikipedia.org/wiki/Universal_algebra) ... it seems that all types that belong to a class are models? E.g. all "monads" have to satisfy the "monad laws" stated in the Monad class, i.e. equational axioms!

Nah, Haskell isn't that strong, it only ensures type integrity, not the laws themselves. Doing that isn't decidable in the genaral case as it'd require source analysis, at least with the current state of types. I better not attempt to answer the rest as I'm way to far off my home turf. Ask Jonathan. -- (c) this sig last receiving data processing entity. Inspect headers for copyright history. All rights reserved. Copying, hiring, renting, performance and/or quoting of this signature prohibited.