Hi!

I have an idea for a signaling simulating halt decider that forks the
simulation into two branches if the input calls the halt decider as
per [Strachey 1965]'s "Impossible Program":

void P(void (*x)())
{ if (H(x, x))
infinite_loop: goto infinite_loop;
return;
}

int main()
{ std::cout << "Input halts: " << H(P, P) << std::endl;
}

When the simulator detects the call to H in P it forks the simulation
into a non-halting branch (returning 0 to P) and a halting branch
(returning 1 to P) and continues the simulation of these two branches
in parallel.

If the non-halting branch is determined to halt AND the halting branch
is determined to not halt then pathology is detected and reported via
a sNaP (signaling Not a Program) signal (analogous to IEEE 754's
sNaN (signaling Not a Number) signal)

If EITHER branch is determined to be correctly decided then that will
be the decision of the halting decider.

Crucially this scheme will handle (and correctly decide) the
following case whereby the result of H is discarded by the input:

void Px(void (*x)())
{ (void) H(x, x);
return;
}

Obviously my idea necessitateS extending the definition of a halt
decider:

1) Decider decision is HALTS if input halts.
2) Decider decision is NON-HALTING if input does not halt.
3) Decider rejects pathological input as invalid by signaling sNaP.

Thoughts? I am probably missing something obvious as my idea
appears to refute [Strachey 1965] and associated HP proofs which
great minds have mulled over for decades.

Mr Flibble <flibble@reddwarf.jmc.corp> writes:

> Obviously my idea necessitateS extending the definition of a halt
> decider:
>
> 1) Decider decision is HALTS if input halts.
> 2) Decider decision is NON-HALTING if input does not halt.
> 3) Decider rejects pathological input as invalid by signaling sNaP.
>
> Thoughts? I am probably missing something obvious as my idea
> appears to refute [Strachey 1965] and associated HP proofs which
> great minds have mulled over for decades.

Stachey was writing about halt deciders, not partial deciders. Just
like the last time you posted this.

--
Ben.

On Thursday, August 11, 2022 at 9:01:00 PM UTC+1, Ben Bacarisse wrote:
> Mr Flibble <fli...@reddwarf.jmc.corp> writes:
>
> > Obviously my idea necessitateS extending the definition of a halt
> > decider:
> >
> > 1) Decider decision is HALTS if input halts.
> > 2) Decider decision is NON-HALTING if input does not halt.
> > 3) Decider rejects pathological input as invalid by signaling sNaP.
> >
> > Thoughts? I am probably missing something obvious as my idea
> > appears to refute [Strachey 1965] and associated HP proofs which
> > great minds have mulled over for decades.
> Stachey was writing about halt deciders, not partial deciders. Just
> like the last time you posted this.

I think he's trying to parody Olcott, though I could be wrong...

It could explain why he's put in a new post which seems to be identical to a previous one.

On Thu, 11 Aug 2022 13:11:37 -0700 (PDT)
Paul N <gw7rib@aol.com> wrote:

> On Thursday, August 11, 2022 at 9:01:00 PM UTC+1, Ben Bacarisse wrote:
> > Mr Flibble <fli...@reddwarf.jmc.corp> writes:
> >
> > > Obviously my idea necessitateS extending the definition of a halt
> > > decider:
> > >
> > > 1) Decider decision is HALTS if input halts.
> > > 2) Decider decision is NON-HALTING if input does not halt.
> > > 3) Decider rejects pathological input as invalid by signaling
> > > sNaP.
> > >
> > > Thoughts? I am probably missing something obvious as my idea
> > > appears to refute [Strachey 1965] and associated HP proofs which
> > > great minds have mulled over for decades.
> > Stachey was writing about halt deciders, not partial deciders. Just
> > like the last time you posted this.
>
> I think he's trying to parody Olcott, though I could be wrong...
>
> It could explain why he's put in a new post which seems to be
> identical to a previous one.

I think parodying Olcott is a great idea: satire is the best weapon
against the immovable bad.

/Flibble

Paul N <gw7rib@aol.com> writes:

> On Thursday, August 11, 2022 at 9:01:00 PM UTC+1, Ben Bacarisse wrote:
>> Mr Flibble <fli...@reddwarf.jmc.corp> writes:
>>
>> > Obviously my idea necessitateS extending the definition of a halt
>> > decider:
>> >
>> > 1) Decider decision is HALTS if input halts.
>> > 2) Decider decision is NON-HALTING if input does not halt.
>> > 3) Decider rejects pathological input as invalid by signaling sNaP.
>> >
>> > Thoughts? I am probably missing something obvious as my idea
>> > appears to refute [Strachey 1965] and associated HP proofs which
>> > great minds have mulled over for decades.
>> Stachey was writing about halt deciders, not partial deciders. Just
>> like the last time you posted this.
>
> I think he's trying to parody Olcott, though I could be wrong...
>
> It could explain why he's put in a new post which seems to be
> identical to a previous one.

Oh, I wish it were so easy to tell. But I like your idea and will run
with it.

Great work Mr Flibble! Hilarious.

--
Ben.

On 8/11/22 1:42 PM, Mr Flibble wrote:
> Hi!
>
> I have an idea for a signaling simulating halt decider that forks the
> simulation into two branches if the input calls the halt decider as
> per [Strachey 1965]'s "Impossible Program":
>
> void P(void (*x)())
> {
> if (H(x, x))
> infinite_loop: goto infinite_loop;
> return;
> }
>
> int main()
> {
> std::cout << "Input halts: " << H(P, P) << std::endl;
> }
>
> When the simulator detects the call to H in P it forks the simulation
> into a non-halting branch (returning 0 to P) and a halting branch
> (returning 1 to P) and continues the simulation of these two branches
> in parallel.
>
> If the non-halting branch is determined to halt AND the halting branch
> is determined to not halt then pathology is detected and reported via
> a sNaP (signaling Not a Program) signal (analogous to IEEE 754's
> sNaN (signaling Not a Number) signal)
>
> If EITHER branch is determined to be correctly decided then that will
> be the decision of the halting decider.
>
> Crucially this scheme will handle (and correctly decide) the
> following case whereby the result of H is discarded by the input:
>
> void Px(void (*x)())
> {
> (void) H(x, x);
> return;
> }
>
> Obviously my idea necessitateS extending the definition of a halt
> decider:
>
> 1) Decider decision is HALTS if input halts.
> 2) Decider decision is NON-HALTING if input does not halt.
> 3) Decider rejects pathological input as invalid by signaling sNaP.
>
> Thoughts? I am probably missing something obvious as my idea
> appears to refute [Strachey 1965] and associated HP proofs which
> great minds have mulled over for decades.
>

As has been mentioned below, you need to work up exactly how you are
going to define the term "pathological input".

Also, it doesn't actually "refute" those proofs, because you don't show
them to be incorrect, as those statement include their definition of a
Halt Decider and Halting that you don't match, so you have a disconnect.