Path: ...!weretis.net!feeder9.news.weretis.net!news.quux.org!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: dbush Newsgroups: comp.theory Subject: Re: DDD specifies recursive emulation to HHH and halting to HHH1 Date: Thu, 27 Mar 2025 14:27:15 -0400 Organization: A noiseless patient Spider Lines: 91 Message-ID: References: <9adf9b9c30250aaa2d3142509036c892db2b7096@i2pn2.org> <211f9a2a284cb2deaa666f424c1ef826fe855e80@i2pn2.org> <3f250e699762cfe6fccc844f10eb04f32d470b6a@i2pn2.org> <8423998561d8feee807509b0ed6335123d35a7c9@i2pn2.org> <448c82acff6b5fc1d2aa266be92df6f778ec2c6a@i2pn2.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Thu, 27 Mar 2025 19:27:15 +0100 (CET) Injection-Info: dont-email.me; posting-host="7b1cdb209801917177bf546dd323d150"; logging-data="899995"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX193KNwxg53bSHAsMkFLbKQd" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:pRTM054dV0MhsL4AFOlZWD82XB8= Content-Language: en-US In-Reply-To: Bytes: 5086 On 3/27/2025 1:50 PM, olcott wrote: > On 3/27/2025 2:18 AM, Fred. Zwarts wrote: >> Op 27.mrt.2025 om 04:09 schreef olcott: >>> On 3/26/2025 8:22 PM, Richard Damon wrote: >>> >>> _DDD() >>> [00002172] 55         push ebp      ; housekeeping >>> [00002173] 8bec       mov  ebp,esp  ; housekeeping >>> [00002175] 6872210000 push 00002172 ; push DDD >>> [0000217a] e853f4ffff call 000015d2 ; call HHH(DDD) >>> [0000217f] 83c404     add  esp,+04 >>> [00002182] 5d         pop  ebp >>> [00002183] c3         ret >>> Size in bytes:(0018) [00002183] >>> >>>> Non-Halting is that the machine won't reach its final staste even if >>>> an unbounded number of steps are emulated. Since HHH doesn't do >>>> that, it isn't showing non-halting. >>>> >>> >>> DDD emulated by any HHH will never reach its final state >>> in an unbounded number of steps. >>> >>> DDD emulated by HHH1 reaches its final state in a finite >>> number of steps. >>> >> It is not very interesting to know whether a simulator reports that it >> is unable to reach the end of the simulation of a program that halts >> in direct execution. > > That IS NOT what HHH is reporting. > HHH correctly rejects DDD because DDD correctly > emulated by HHH cannot possibly reach its own > final halt state. In other words, HHH is not a halt decider because it is not computing the required mapping: Given any algorithm (i.e. a fixed immutable sequence of instructions) X described as with input Y: A solution to the halting problem is an algorithm H that computes the following mapping: (,Y) maps to 1 if and only if X(Y) halts when executed directly (,Y) maps to 0 if and only if X(Y) does not halt when executed directly > >> It is interesting to know: >> 'Is there an algorithm that can determine for all possible inputs >> whether the input specifies a program that (according to the semantics >> of the machine language) halts when directly executed?' > > It is the halts while directly executed that is impossible > for all inputs. In other words, you *once again* explicitly agree with Linz and others that no algorithm behaves as required above. > A TM can only report on the behavior that the machine code > of another TM specifies. And the machine code of DDD specifies that it halts when executed directly. > When it specifies a pathological > relationship then the behavior caused by the pathological > relationship MUST BE REPORTED. False. The behavior that must be reported is what the requirements stipulate: Given any algorithm (i.e. a fixed immutable sequence of instructions) X described as with input Y: A solution to the halting problem is an algorithm H that computes the following mapping: (,Y) maps to 1 if and only if X(Y) halts when executed directly (,Y) maps to 0 if and only if X(Y) does not halt when executed directly > >> This question seems undecidable for Olcott. >> >> > >