Sujet : Re: Every D(D) simulated by H presents non-halting behavior to H ###
De : polcott333 (at) *nospam* gmail.com (olcott)
Groupes : comp.lang.c comp.lang.c++Date : 22. May 2024, 15:59:24
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v2l18c$17mu1$2@dont-email.me>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
User-Agent : Mozilla Thunderbird
On 5/22/2024 3:50 AM, David Brown wrote:
On 21/05/2024 22:13, Keith Thompson wrote:
David Brown <david.brown@hesbynett.no> writes:
[...]
However, my point was that the common excuse of "I hate this crime so
much I lashed out" is not a valid excuse.
[...]
>
And you could have made that point without accompanying it by a long
article about various kinds of child abuse in a newsgroup that's
supposed to be about C.
>
You didn't have to let yourself be trolled.
>
I don't consider James' post to be trolling. But of course that in itself does not mean it is appropriate to reply here. However, I replied to that post in the group (rather than email) because it seemed to me that a point I had made previously needed clarification.
As has been pointed out by others, topicality in this thread was doomed from the first post. I'd be happier if Olcott had never cross-posted here, but we can't change that.
*Someone could simply answer the question instead of*
*spending countless messages on dodging the question*
For every H/D pair matching the following template where
H is a pure function:
Does any D correctly simulated by H reach its own line 06 and
halt or does the fact that D remains stuck in recursive simulation
prevent that?
typedef int (*ptr)(); // ptr is pointer to int function in C
00 int H(ptr p, ptr i);
01 int D(ptr p)
02 {
03 int Halt_Status = H(p, p);
04 if (Halt_Status)
05 HERE: goto HERE;
06 return Halt_Status;
07 }
08
09 int main()
10 {
11 H(D,D);
12 return 0;
13 }
It is trivial to see that for every H/D pair of the infinite
set of H/D pairs that match the above template that
D correctly simulated by H cannot possibly reach its own final
state at line 06 and halt because D correctly simulated by
H remains stuck in recursive simulation.
This provides the basis for simulating termination analyzer H to
correctly determine that the halting problem's counter-example
input D cannot possibly halt.
-- Copyright 2024 Olcott "Talent hits a target no one else can hit; Geniushits a target no one else can see." Arthur Schopenhauer