On 3/19/07, Nicolas Frisby <nicolas.frisby@gmail.com> wrote:
Nope, but I believe the two are equipotent. This usage of "believe" is
one of those "I think I remember reading it somewhere" usages.
On 3/19/07, Henning Thielemann <
lemming@henning-thielemann.de> wrote:
>
> On Sat, 17 Mar 2007, Nicolas Frisby wrote:
>
> > Bekic's lemma [1], allows us to transform nested fixed points into a
> > single fixed point, such as:
> >
> > fix (\x -> fix (\y -> f (x, y))) = fix f where f :: (a, a) -> a
>
> The 'fix' on the right hand side is not the standard one (e.g.
> Control.Monad.Fix), is it?
Yes, it is the standard "fix". The Bekic lemma actually reads:
fix (\x -> fix (\y -> f (x, y))) = fix (\x -> f (x, x))
which should explain the confusion here.
-Levent.