Universality

[Jordan B Pollack]

Sontag refers to the turing machine construction in a chapter of my
unpublished thesis.  I showed that it is SUFFICIENT to have rational
values (to store the unbounded tape), Multiplicative connections (to
GATE the rational values), and thresholds (to make decisions).  My
construction was modelled on Minsky's stored program machine
construction (using unbounded integers) in his book FINITE AND
INFINITE MACHINES. I was not able to formally prove NECESSITY of the
conjunction of parts.

My work was misinterpreted as a suggestion that we should build a
Turing machine out of neurons, and then use it! The actual reason for
this kind of exercise is to make sure we are not missing something as
important to neural computing as, say, "Branch-If-Zero" is to
conventional machines.

The chapter is available the usual way from neuroprose as

pollack.neuring.ps.Z

If "the usual way" is difficult for you, you might try 
getting the file "Getps" the usual way, and then FTP'ing
from neuroprose becomes quite easy.