Re: Simulating termination analyzers by dummies --- What does halting mean?

Am Tue, 18 Jun 2024 13:16:42 -0500 schrieb olcott:

On 6/18/2024 12:57 PM, joes wrote:

Am Tue, 18 Jun 2024 12:25:44 -0500 schrieb olcott:

On 6/18/2024 12:06 PM, joes wrote:
void DDD()
{
    H0(DDD);
}
DDD correctly simulated by any H0 cannot possibly halt.

DDD halts iff H0 halts.

So H0 returns "doesn't halt" to DDD, which then stops running, so H0
should have returned "halts".

No counterargument?

Some TM's loop and thus never stop running, this is classical
non-halting behavior. UTM's simulate Turing machine descriptions.
This is the same thing as an interpreter interpreting the source-code
of a program.

Some TMs do not loop and do not halt.

Different people define these terms differently and that gets stuck in
the infinite loop of the meaning of words.

"Looping" means returning to the same combined state of TM+tape.
Halting means arriving at an internal state marked final (no successors).

A UTM can be adapted so that it only simulates a fixed number of
iterations of an input that loops. When this UTM stops simulating this
Turing machine description we cannot correctly say that this looping
input halted.

Yes. We also cannot say that that input was simulated correctly.

Yes everyone does that thinking that their unsupported proclamation
proves itself until I ask them:
Exactly which step was simulated incorrectly?
Then they clam up and use double-talk and change the subject.

Fuck you. The simulation must be complete. The steps that follow and
weren't simulated at all were "simulated incorrectly".

--
joes