[Haskell-cafe] Re: Are arbitrary rank types and existentials equivalent?

[Larry Evans]

On 11/09/08 17:04, Loup Vaillant wrote:
[snip]
> Err, where can I find such texts? I don't even understand
> "intuitionistic predicate logic" :-(
I just googled that phrase and got many hits.
I think metaprl implements something like that:

   http://metaprl.org/default.html

I've often wondered about haskell and metaprl.
I know metprl has something like a hierarchy of
types and that's used to avoid Russell's paradox.
I also remember reading somewhere (can't remember where)
that there was something in category theory that
had a hierarchy of categories.

Maybe someone else can provide more details.