Path: news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: "Fred. Zwarts" Newsgroups: comp.theory Subject: Re: DDD specifies recursive emulation to HHH and halting to HHH1 Date: Sun, 30 Mar 2025 16:06:33 +0200 Organization: A noiseless patient Spider Lines: 66 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sun, 30 Mar 2025 16:06:33 +0200 (CEST) Injection-Info: dont-email.me; posting-host="2f5a5d73b9c0193d8d0ef7f30f611d28"; logging-data="1617588"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+fC0AXHGb3zcbzLIojNc1V" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:kMCmoPX6v2DhRzbMihqGsSkn4AA= Content-Language: nl, en-GB In-Reply-To: Op 29.mrt.2025 om 22:07 schreef olcott: > On 3/29/2025 3:45 PM, Fred. Zwarts wrote: >> Op 29.mrt.2025 om 20:03 schreef olcott: >>> On 3/29/2025 10:23 AM, dbush wrote: >>>> On 3/29/2025 11:12 AM, olcott wrote: >>>>> On 3/28/2025 11:00 PM, dbush wrote: >>>>>> On 3/28/2025 11:45 PM, olcott wrote: >>>>>>> >>>>>>> It defines that it must compute the mapping from >>>>>>> the direct execution of a Turing Machine >>>>>> >>>>>> Which does not require tracing an actual running TM, only mapping >>>>>> properties of the TM described. >>>>> >>>>> The key fact that you continue to dishonestly ignore >>>>> is the concrete counter-example that I provided that >>>>> conclusively proves that the finite string of machine >>>>> code input is not always a valid proxy for the behavior >>>>> of the underlying virtual machine. >>>> >>>> In other words, you deny the concept of a UTM, which can take a >>>> description of any Turing machine and exactly reproduce the behavior >>>> of the direct execution. >>> >>> I deny that a pathological relationship between a UTM and >>> its input can be correctly ignored. >>> >>> When this pathological relationship changes this behavior >>> we cannot simply pretend that the behavior is not changed. >>> >>> >> >> When solving a problem, it is stupid to choose a tool that has a >> pathological relation with the problem. > > A termination analyzer cannot reject itself, yet it can > reject an input. This input was intentionally defined > to try to fool this termination analyzer. > > int DD() > { >   int Halt_Status = HHH(DD); >   if (Halt_Status) >     HERE: goto HERE; >   return Halt_Status; > } > > On the other hand when this same input DD is simulated > by the termination analyzer that DD defined a pathological > relationship to IT DOES SPECIFY NON-TERMINATING BEHAVIOR. > We can ask whether we can create a hammer that can hit all possible nails on the head. It can be proven that no such hammer exists, because we can always attach a nail to the hammer upside down, so that the hammer cannot hit it on its head. Olcott would call that a 'pathological relationship' between hammer and nail. I think he would argue that for such a pathological relationship between hammer and nail we need another definition of 'hitting behaviour', because the original requirement ignores the pathological relationship. So, when we define a 'hitting behaviour' as when the hammer is halfway down in an attempt to reach the nail, we see that he can construct a hammer and say that it correctly shows 'hitting behaviour' to the nail when it is halfway down, because the requirement to hit it on the head is logically impossible. :-)