From: Marius Nita <marius@cs.washington.edu>
To: padator@wanadoo.fr
Cc: Oliver Bandel <oliver@first.in-berlin.de>, caml-list@inria.fr
Subject: Re: [Caml-list] Lambda-Term (f x) (x f) translated to Ocaml?
Date: Mon, 27 Mar 2006 16:55:54 -0800 [thread overview]
Message-ID: <4428899A.9090803@cs.washington.edu> (raw)
In-Reply-To: <24000351.1143506695382.JavaMail.www@wwinf1608>
yoann padioleau wrote:
>> Hello,
>>
>> I'm not firm in lambda calculus, what is the lambda-term
>> in the subject translated to OCaml?
>>
>> Is this possible?
>
> the ocaml interpreter dont want this definition
>
> let g f x = (f x) (x f)
>
> and shout:
> this expression has type ('a -> 'b) -> 'c -> 'd but is here used with type 'a
>
> I guess that this is not a lambda term that can be typed.
> There are many of them. A famous one is the Y combinator.
> The _typed_ lambda calculus does not allow all the lambda terms
> of the (normal) lambda calculus.
g can't be written, but (f x) (x f) works for suitable values for f and
x :) Namely if f = x = id. There's probably some deep parametricity
property at the heart of it.
-marius
next prev parent reply other threads:[~2006-03-28 0:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-28 0:44 yoann padioleau
2006-03-28 0:55 ` Marius Nita [this message]
2006-03-28 1:11 ` Oliver Bandel
2006-03-31 21:01 ` Thomas Fischbacher
2006-03-31 23:53 ` yoann padioleau
-- strict thread matches above, loose matches on Subject: below --
2006-03-28 0:07 Oliver Bandel
2006-03-31 20:58 ` [Caml-list] " Thomas Fischbacher
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