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Re: Turing vs. Godel (Newbie Question)

Subject: Re: Turing vs. Godel (Newbie Question)
From: Alan Smaill <smaill@xxxxxxxxxxxxxxxx>
Date: Wed, 04 Oct 2006 12:09:33 +0100
Newsgroups: sci.logic, sci.math
"Charlie-Boo" <shymathguy@xxxxxxxxx> writes:

> Alan Smaill wrote:
>
>> OK, let's take this one step at a time.
>> I'll use some of the nuprl rules (simplified a bit, but
>> we could use them as given).  Let's look at the following
>> problem.
>>
>> Terms of the lambda calculus are programs, I hope you
>> agree.
>>
>>   en.wikipedia.org/wiki/Lambda_calculus
>>
>> gives more detail.  Some of these programs can be typed,
>> e.g. (using \ for lambda) \x.(\y.x) has type A -> (B -> A)
>> for types A,B.  Now let's use Curry-Howard to solve
>> the following problem.  Given a type (formed from
>> base types A,B,C,... with the only connective ->), find a program
>> of that type.
>
>  . . . [see original post for snipped details]
>
>>   [2] complete
>>   ==> u(1)in u(2)
>>   by intro
>
>> Let me know what you would like clarified and we can continue
>> to see the automatic derivation of a program from this proof.
>
> 1. What does the resulting program do?

As I said, so far we only have the proof.
So it is not yet time to clarify this, as I have not presented it yet.

> 2. What is its input?
>
> 3. What is its output?
>
> 4. What is the relationship between its input and output?
>
> 5. What is the formal representation of the request that the user
> enters to create this program?
>
> 6. What are the resulting programs?
>
> 7. How does each execute - what is the algorithm that is executed?

Same answer applies.

So, can I take it that you are clear so far that we have entered a statement
to be proved:

a:u(1)=>b:u(1)=>c:u(1)=>(a=>b=>c)=>(a=>b)=>a=>c

and found a proof in the formal system given in my previous post?

If so, I will show how we can extract a program automatically from this proof
and then answer the questions above.

> What would be the input to request the following fundamental functions:

One thing at a time;
I will gladly address the other questions also, when and if
you are happy with this simple example.

> Thank you for explaining how your Program Synthesis system works.
>
> I would be glad to answer these questions (8-13) using a
> Computationally Based Logic.  (Many of them are explicitly answered in
> my ARXIV paper.)

This is not about CB and his system;
it is about CB's claim that there is no (other) account of
program synthesis.

>
> C-B
>

-- 
Alan Smaill

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