Proof: Simulating self is not possible (from all real programs, everyIt is possible for a UTM to simulate itself simulating another program.
one can verify).
This also implies UTM does not exist.Since they do, your premise or deduction must be wrong.
Did Turing made a mistake?Probably not.
Proof: Simulating self is not possible (from all real programs, every one can verify).
This also implies UTM does not exist.
Did Turing made a mistake? https://en.wikipedia.org/wiki/Universal_Turing_machine
Proof: Simulating self is not possible (from all real programs, every
one can verify).
This also implies UTM does not exist.
Did Turing made a mistake?
On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:
On 10/25/24 1:12 PM, wij wrote:
Proof: Simulating self is not possible (from all real programs, every one can verify).
This also implies UTM does not exist.
Did Turing made a mistake?
https://en.wikipedia.org/wiki/Universal_Turing_machine
The key point you are missing is that if the UTM emulating a program
like H^ (without the contrary nature at the end), so that we can get the
infinite chain of UTM emulating that UTM emulating that UTM ..., it just
ends up being a non-halting computation, and thus the non-halting
emulation of that computation is exactly right.
The problem is if you want it to be a UTM and also a decider, then you
run into the problem.
The UTM chain *IS* an infinite deep recursive simulation, which is just
like the infinite-recursion, which is non-halting.
When you change the UTM to be a decider (and thus no longer a UTM) it
finds it can't know the answer for the behavior of the UTM it was
previously.
Simulator::= A TM (utm) that performs the same function as its argument TM (f).
IOW, utm(f)=f (or utm(f,arg)=f(arg))
In case of self-simulation "utm(utm)" ... well, the argument utm has no argument
(empty tape?) to define its behavior. What is the outer utm supposed to 'simulate'?
How do you define 'simulator'? What exactly does UTM simulate?
On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:You also need an input for the simulated machine. I suppose you would
On 10/25/24 1:12 PM, wij wrote:
Proof: Simulating self is not possible (from all real programs, everyThe key point you are missing is that if the UTM emulating a program
one can verify).
This also implies UTM does not exist.
Did Turing made a mistake?
like H^ (without the contrary nature at the end), so that we can get
the infinite chain of UTM emulating that UTM emulating that UTM ..., it
just ends up being a non-halting computation, and thus the non-halting
emulation of that computation is exactly right.
The problem is if you want it to be a UTM and also a decider, then you
run into the problem.
The UTM chain *IS* an infinite deep recursive simulation, which is just
like the infinite-recursion, which is non-halting.
When you change the UTM to be a decider (and thus no longer a UTM) it
finds it can't know the answer for the behavior of the UTM it was
previously.
Simulator::= A TM (utm) that performs the same function as its argument
TM (f).
IOW, utm(f)=f (or utm(f,arg)=f(arg))
In case of self-simulation "utm(utm)" ... well, the argument utm has no argument (empty tape?) to define its behavior. What is the outer utm
supposed to 'simulate'?
How do you define 'simulator'? What exactly does UTM simulate?
On Sat, 2024-10-26 at 11:35 -0400, Richard Damon wrote:lolwut? The transition function is not modified, that would make it
On 10/26/24 10:08 AM, wij wrote:That's right. You need to REPROGRAM. You need to modify the transition function and the symbols, and the tape contents.
On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:So, what does utm() do, one good definition is just halt.
On 10/25/24 1:12 PM, wij wrote:
Proof: Simulating self is not possible (from all real programs,The key point you are missing is that if the UTM emulating a
every one can verify).
This also implies UTM does not exist.
Did Turing made a mistake?
program like H^ (without the contrary nature at the end), so that
we can get the infinite chain of UTM emulating that UTM emulating
that UTM ..., it just ends up being a non-halting computation, and
thus the non-halting emulation of that computation is exactly
right.
The problem is if you want it to be a UTM and also a decider, then
you run into the problem.
The UTM chain *IS* an infinite deep recursive simulation, which is
just like the infinite-recursion, which is non-halting.
When you change the UTM to be a decider (and thus no longer a UTM)
it finds it can't know the answer for the behavior of the UTM it
was previously.
Simulator::= A TM (utm) that performs the same function as its
argument TM (f).
IOW, utm(f)=f (or utm(f,arg)=f(arg))
In case of self-simulation "utm(utm)" ... well, the argument utm has
no argument (empty tape?) to define its behavior. What is the outer
utm supposed to 'simulate'?
How do you define 'simulator'? What exactly does UTM simulate?
thus utm(utm) would emulate utm() which would just see it doesn't have
an input and halt.
UTMs are given a "description" of the Turing Machne and of its input,
expressed in the "language" of the UTM.
A simple (to understand,complicated to build) would be one where you
give as an input listing of every possible state the machine could be
in and every possible input character, and lists the resulting state,
character to put on the tape, and tape motion, and the starting state,
Then you put the contents of the tape that machine is to process with
the current pointer of the starting point.
The UTM then just applies the rules described in the first part, to the
tape described in the second part, and when it gets to a state marked
as a final state (perhaps one of the tape operations is "Halt", or
states are marked as terminal) it stops and returns the results.
This means that the UTM just "zimulates" the execution process of a
Turing Machine, where one "step" takes the current state, and the
contents of the tape at its current position, and updates the tape to
the new value and move the current location of the tape, and updates
the current state.
The "proof" of the existance of a UTM was the proof that a Turing
Machine could be programmed to do that set of transformations.
Therefore, "No real UTM exists". "An Univeral TM" is a false idea.
On Sat, 2024-10-26 at 11:35 -0400, Richard Damon wrote:
On 10/26/24 10:08 AM, wij wrote:
On Fri, 2024-10-25 at 18:17 -0400, Richard Damon wrote:
On 10/25/24 1:12 PM, wij wrote:
Proof: Simulating self is not possible (from all real programs, every one can verify).
This also implies UTM does not exist.
Did Turing made a mistake?
https://en.wikipedia.org/wiki/Universal_Turing_machine
The key point you are missing is that if the UTM emulating a program
like H^ (without the contrary nature at the end), so that we can get the >>>> infinite chain of UTM emulating that UTM emulating that UTM ..., it just >>>> ends up being a non-halting computation, and thus the non-halting
emulation of that computation is exactly right.
The problem is if you want it to be a UTM and also a decider, then you >>>> run into the problem.
The UTM chain *IS* an infinite deep recursive simulation, which is just >>>> like the infinite-recursion, which is non-halting.
When you change the UTM to be a decider (and thus no longer a UTM) it
finds it can't know the answer for the behavior of the UTM it was
previously.
Simulator::= A TM (utm) that performs the same function as its argument TM (f).
IOW, utm(f)=f (or utm(f,arg)=f(arg))
In case of self-simulation "utm(utm)" ... well, the argument utm has no argument
(empty tape?) to define its behavior. What is the outer utm supposed to 'simulate'?
How do you define 'simulator'? What exactly does UTM simulate?
So, what does utm() do, one good definition is just halt.
thus utm(utm) would emulate utm() which would just see it doesn't have
an input and halt.
UTMs are given a "description" of the Turing Machne and of its input,
expressed in the "language" of the UTM.
A simple (to understand,complicated to build) would be one where you
give as an input listing of every possible state the machine could be in
and every possible input character, and lists the resulting state,
character to put on the tape, and tape motion, and the starting state,
Then you put the contents of the tape that machine is to process with
the current pointer of the starting point.
The UTM then just applies the rules described in the first part, to the
tape described in the second part, and when it gets to a state marked as
a final state (perhaps one of the tape operations is "Halt", or states
are marked as terminal) it stops and returns the results.
This means that the UTM just "zimulates" the execution process of a
Turing Machine, where one "step" takes the current state, and the
contents of the tape at its current position, and updates the tape to
the new value and move the current location of the tape, and updates the
current state.
The "proof" of the existance of a UTM was the proof that a Turing
Machine could be programmed to do that set of transformations.
That's right. You need to REPROGRAM. You need to modify the transition function and
the symbols, and the tape contents.
Therefore, "No real UTM exists". "An Univeral TM" is a false idea.
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