[FOM] Feasible and Utterable Numbers

[V.Sazonov@csc.liv.ac.uk]

Quoting Ritwik Bhattacharya <ritwik at cs.utah.edu> Mon, 07 Aug 2006:

>> Thus, this number is definitely non-feasible (in our current world) 
>> in the sense that no physical computer could calculate its value in 
>> the form SSSS...0 (a term a bigger size than our World!).
> Why do you say that? The fact that the number of electrons in the 
> universe is less than a number only means that there is no way to 
> represent that number "at once".

In general, real (feasible) computational practice requires to have any 
information saved somewhere "at once".

But imagine a TM that spits out a
> digit at a time, and then overwrites the location. Surely you need a 
> much smaller number of electrons to thus represent any number, 
> including a number larger than the number of electrons.

Where in the World will you put all these digits if they will be needed 
in a future computation?

Vladimir Sazonov


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