[plt-scheme] The Lambda Calculus behind functional programming

On Sun, Sep 02, 2007 at 12:05:58AM +0200, Jos Koot wrote:
> 
> 
> ((((lambda(x)((((((x x)x)x)x)x)x))
>   (lambda(x)(lambda(y)(x(x y)))))
>  (lambda(x)(write x)x))
> 'greeting)
> ----- Original Message ----- 
> From: <hendrik at topoi.pooq.com>
> To: <plt-scheme at list.cs.brown.edu>
> Sent: Saturday, September 01, 2007 10:14 PM
> Subject: Re: [plt-scheme] The Lambda Calculus behind functional programming
> 
> 
> >On Sat, Sep 01, 2007 at 02:53:58PM +0200, Jos Koot wrote:
> >>----- Original Message ----- 
> >>From: "Jens Axel Søgaard" <jensaxel at soegaard.net>
> >>To: "Jos Koot" <jos.koot at telefonica.net>
> >>Cc: "PLT Scheme" <plt-scheme at list.cs.brown.edu>
> >>Sent: Friday, August 31, 2007 8:38 PM
> >>Subject: Re: [plt-scheme] The Lambda Calculus behind functional 
> >>programming
> >>
> >>
> >>>Jos Koot wrote:
> >>>>Would it make sense to present a formal mathematical definition of a 
> >>real
> >>>>number on primary school as a starting point for elementary arithmetics?
> >
> >formal??? probably not.  Informal? maybe.  The essence that has to be
> >conveyed is
> > You've got a real number when you can approximate it as precisely as
> >you want.
> 
> 
> Given an arbitrary real number you can approximate it
> as precisely as you want by means of fractions
> (unless "as precisely as you want" includes approximation-approximated=0)

That's exactly what I mean.  The essence or real numbers is their 
approximability by rationals.

> Therefore I do not understand what you mean.

I think you do.  You just said it yourself.  You just didn't think I 
could be meaning that.

> 
> Jos Koot
> 

-- hendrik