On Wed, Oct 31, 2018 at 3:14 PM Philip Thrift <cloudver...@gmail.com> wrote:

>From  https://www.cs.auckland.ac.nz/~cristian/talks/selected/BeamerATM.pdf
>
> *> An accelerated Turing machine (sometimes called Zeno machine) is a
> Turing machine that takes 2^−n units of time (say seconds) to perform its
> nth step; we assume that steps are in some sense identical except for the
> time taken for their execution.*
>

You can assume anything you like and you can define a dragon as a fire
breathing flying reptile if you like, but definitions don't cause something
to suddenly come into existence.

> *The following ATM can solve the halting problem of an arbitrarily given
> TM T and input w in finite time: *
>

The creator of this ATM made a crucial assumption namely "we assume that
steps are in some sense identical except for the time taken for their
execution". To me that is equivalent to saying at the end of step 3 in a
mathematical proof just before going to step 4 "at this point we assume a
miracle occurs". But there is a even more fundamental problem,  solving the
Halting Problem is logically contradictory.

If the ATM can solve the Halting problem then if I feed in any problem it
can tell me if it halts or not. Let's say the ATM has 2 slots for input and
one slot for output, if I feed in the circuit logic design blueprints of
any computer into one slot the ATM can simulate that computer, and if I
feed in  program data into the other slot that ATM  will output either
"Halt" meaning the simulated machine operating on that data will stop or
the ATM will output "not halt" meaning  the simulated machine operating on
that data will not stop.

I will now make a new machine called X, it has 3 parts to it. The first
part of X  is just a Xerox copy machine, feed in one program and it outputs
2 identical programs. The second part of X is the ATM and it receives the 2
programs as input from the Xerox machine's outputs, and the ATM then
outputs either "halt" or "not halt". The third and last part of X is a very
simple machine called the negator, it receives as input the output of the
ATM and if the input to the negator is "Halt" the negator will go into a
infinite loop and if the input is "not halt" the negator will print "halt"
and then stop.

Now lets draw the blueprint circuit design of the entire X machine that
fully defines it, then make 2 copies of it and feed it into the ATM; so the
ATM is now trying to figure out if the X machine will halt if it is fed its
own blueprint as data. If the ATM says "halt" the X machine will not halt
and the ATM was wrong.  If the ATM says "not halt" the X machine will halt
and the ATM was wrong again.

Therefore the ATM can not logically exist.

John K Clark

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