[PRL] the simplest universal turing machine

[Peter R. Douglass]

Use the P and A combinators, and you eliminate the tree structure.
--PeterD

Felix S Klock II wrote:
> Doesn't using the X combinator requires encoding the tree structure  
> of your terms in some manner?
>
> I'm not sure that Wolfram's models are easily compared to tree  
> structures terms. . .
>
> On Oct 26, 2007, at 7:24 PM, Carl Eastlund wrote:
>
>   
>> It always surprises me how worked up the Wolfram Research folks get
>> over finding new, small, Turing-complete models of computation.  I
>> always thought they were a dime a dozen.  In any event, if they're
>> impressed by a 2-state, 3-color Turing machine, someone should show
>> them the X combinator.
>>
>> On 10/26/07, Dimitris Vardoulakis <dimvar at ccs.neu.edu> wrote:
>>     
>>> http://blog.wolfram.com/2007/10/the_prize_is_won_the_simplest.html
>>>
>>>       
>> -- 
>> Carl Eastlund
>>
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>
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