On Sat, 20 Aug 2022 16:01:31 -0500, in article <crudnRbncP4E1pz-
nZ2dnZfq...@giganews.com>, olcott wrote:
[snip]
> It is common knowledge that [...]
Have you noticed that almost every time you use this phrase, you're
wrong?
So also this time.
> [...] the correct and complete simulation of a
> machine description [...]
Machine descriptions are never simulated -- they're just sequences
of symbols.
and don't have any defined behaviour. The machines they *represent*
may be
simulated.
> [...] always provides the actual behavior specified by
> this machine description.
This is almost, but not quite, correct (if you fix it according to
the
previous paragraph). It would have been completely correct, if it
weren't
for the fact that you're using an utterly bizarre meaning for the
phrase
"the actual behavior specified by this machine description".
> That you and others reject this when it is applied to my simulating halt
> decider implicitly rejects the notion of a UTM. Since you and others do
> accept the notion of a UTM, I have just proven that your reasoning is
> incoherent and/or inconsistent.
Let M be a given machine, with machine description [M], and let w
be
a given input tape, with tape description [w]. Then the
"simulation"
UTM([M],[w]) has exactly the same result (i.e. exactly the same
behaviour)
as the direct computation M(w). This is actually the definition of
a UTM.
Another way of expressing this is: M(w) and UTM([M],[w]) compute
the same
partial function.
You have made it abundantly clear that when you say "the actual
behavior
specified by this machine description", you do *not* mean "the
actual
behavior specified by this machine description", because that's
simply
the behaviour of M(w). What you *do* mean is "the behaviour of your
particular, broken and incomplete, quasi-simulation based on [M]
and [w]".
Why is it broken? Because it *doesn't* have the same behaviour as M
(w),
nor as UTM([M],[w]). A correct simulation *means* that it has the
same
behaviour as M(w).
Why is it incomplete? Because it aborts its "simulation" before it
reaches
a halting configuration of the machine represented by its input,
and it
does so on invalidly.
Why is it a quasi-simulation? Because it depends on external input
that is
contained in neither [M] nor [w]. You have said, on numerous
occasions,
that the behaviour of your "H(P,P)" depends on the specific memory
location of "P". Well, then that location is an external input.
Your H is
*not* analogous to Linz' H([M],[w]).
This is the point where you usually barf up your stanza about how
the
behaviour of your "H(P,P)" cannot be expected to be computed "from
the
non-input P(P)". This is obviously idiotic, for the following
reasons:
1) A purported halt decider H([M],[w]) is *not* required to compute
its
result *from* M(w), but to *match* M(w). Computing *from* M(w)
would be
completely pointless, because the decider would already know the
answer.
Since you seem unable to understand anything but arguments from
analogy, let me re-use one that you yourself have employed:
Suppose
we want to construct an addition algorithm add(x,y). If you were
to
complain that add(5,7) cannot be required to compute its result
"from
the non-input 12", you would, quite rightly, be regarded as a
complete
nitwit. Can you now guess why you're universally regarded as a
complete
nitwit?
2) The behaviour of UTM([M],[w]) is *defined* to match the
behaviour of M(w),
and UTMs very evidently do exist. The information contained in
[M] and [w]
is obviously enough to match the behaviour of M(w). The fact
that your
"simulator" fails in this regard, is proof that your
"simulator" is
defective -- *not* that you have discovered a "loop hole", or
that halting
theorem is faulty, or anything of that kind -- only that you're
working
with a broken simulator.
> *NO ONE CAN POINT OUT AN ERROR WITH THIS BECAUSE THERE IS NO ERROR*
A lot of people have pointed out many kinds of errors in your
reasoning.
You usually respond with some form "proof by regurgitation". I
expect you
will do so to this post.
> When-so-ever a simulating halt decider (SHD) correctly performs a
> partial simulation of its input and the behavior of this partial
> simulation correctly matches a non-halting behavior pattern then the SHD
> halt decider can correctly report non-halting.
>
> A non-halting behavior pattern is correct when-so-ever matching this
> behavior pattern proves that the correct and complete simulation of the
> input by SHD would never reach the final state of this simulated input.
Yeah, that's just a bunch of equivocations on "correctly", "its
input",
"non-halting behavior", and more. Please learn to write clearly.
Also, could you *please* stop misreading Linz! He *doesn't* say
that a TM
halts, only if it enters a "final state". What he actually says is:
"A Turing machine is said to halt whenever it reaches a
configuration
for which delta is not defined; this is possible because delta
is a
partial function. In fact, we will assume that no transitions
are
defined for any final state, so the Turing machine will halt
whenever
it enters a final state."
So, for a general TM, there may well be configurations for which
the TM
halts in a non-final state. It is, on the other hand, understood
that a TM
*only* stops running if enters a configuration for which the
transition
function is undefined.
"Final states" only concern the *interpretation* of the value of a
computation -- *not* whether the TM halts or not.
This means that "halting" and "stops running" are the exact the
same things.
And obviously, "running" and "being simulated" are two entirely
different
things.