Path: ...!feeds.phibee-telecom.net!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Mikko Newsgroups: comp.theory Subject: Re: Sequence of sequence, selection and iteration matters Date: Tue, 9 Jul 2024 09:22:29 +0300 Organization: - Lines: 53 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 09 Jul 2024 08:22:30 +0200 (CEST) Injection-Info: dont-email.me; posting-host="878bc7b14af3ac60a7596dce9c4398ba"; logging-data="1361114"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX187MBZ4po8QBgHBJGzDWJt5" User-Agent: Unison/2.2 Cancel-Lock: sha1:zDatjwGCj+nUF5pMiiDa+nq7LfE= Bytes: 3028 On 2024-07-08 13:04:13 +0000, olcott said: > On 7/8/2024 2:22 AM, Mikko wrote: >> On 2024-07-07 14:16:10 +0000, olcott said: >> >>> _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] >>> >>> Sufficient knowledge of the x86 language conclusively proves >>> that the call from DDD correctly emulated by HHH to HHH(DDD) >>> cannot possibly return for any pure function HHH. >> >> Suffifcient knowledge of the x86 language makes obvious that >> DDD returns if and only if HHH returns. > > That is insufficient knowledge. Sufficient for the particular purpose. Possibly insufficient for some other purpose. > Sufficient knowledge proves that > DDD correctly simulated by HHH meets this criteria. A false claim is not knowledge. > > If simulating halt decider H correctly simulates its input D > until H correctly determines that its simulated D would never > stop running unless aborted then > > H can abort its simulation of D and correctly report that D > specifies a non-halting sequence of configurations. > > >> Whether a partial simulation of DDD simulates the return depends >> on the simulator. > > That is false proving that you have insufficient knowledge. It is true. There are partial simulators that do simulate D(I) to its termination (if it terminates) and there are simulators that don't. That you cannot imagine something does not mean it can't exist. -- Mikko