[Haskell-cafe] Re: Non-termination of type-checking

2010-01-29 Thread Matthieu Sozeau
Le 29 janv. 10 à 02:56, o...@okmij.org a écrit : Here is a bit more simplified version of the example. The example has no value level recursion and no overt recursive types, and no impredicative polymorphism. The key is the observation, made earlier, that two types c (c ()) and R

[Haskell-cafe] Non-termination of type-checking

2010-01-27 Thread Matthieu Sozeau
Dear Haskellers, while trying to encode a paradox recently found in Coq if one has impredicativity and adds injectivity of type constructors [1] I stumbled on an apparent loop in the type checker when using GADTs, Rank2Types and EmptyDataDecls. {-# OPTIONS -XGADTs -XRank2Types

Re: [Haskell-cafe] The container problem

2008-09-27 Thread Matthieu Sozeau
Le 27 sept. 08 à 15:24, Andrew Coppin a écrit : David Menendez wrote: I wouldn't say that. It's important to remember that Haskell class Monad does not, and can not, represent *all* monads, only (strong) monads built on a functor from the category of Haskell types and functions to itself.

Re: [Haskell-cafe] Associative Commutative Unification

2008-08-27 Thread Matthieu Sozeau
Le 12 juil. 08 à 04:02, John D. Ramsdell a écrit : CIMe[1] might be useful to solve the generated diophantine equations. It also has AC unification, and it probably wouldn't be all that hard to translate our code into OCaml. I think CiME isn't supported anymore. Still it's worth

Re: [Haskell-cafe] OT - lamba calculus definition - alpha reduction

2006-05-29 Thread Matthieu Sozeau
will be lucky. ;-) If b and c are free, then no, they can't be considered equal, and i don't see how you can find a common meaning in this case either. Those two are equivalent: (\b.\x.x b x) = (\c.\x.x c x). -- Matthieu Sozeau http://mattam.org___