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: wij Newsgroups: comp.theory Subject: Re: Every sufficiently competent C programmer knows --- Semantic Property of Finite String Date: Sat, 15 Mar 2025 00:01:12 +0800 Organization: A noiseless patient Spider Lines: 66 Message-ID: <6c64432865001be54d691f8ef0cc89ddc71d18b6.camel@gmail.com> References: <5429f6c8b8a8a79e06b4aeefe677cc54a2a636bf@i2pn2.org> <924e22fc46d629b311b16a954dd0bed980a0a094@i2pn2.org> <0c100c3673494d00bdc02acd44b2d5b930bd2212.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Injection-Date: Fri, 14 Mar 2025 17:01:13 +0100 (CET) Injection-Info: dont-email.me; posting-host="a499a0831bd7f6466cd8a05ed4720a40"; logging-data="1693018"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/DH9+4PbNz11VYBu1bLYqR" User-Agent: Evolution 3.54.3 (3.54.3-1.fc41) Cancel-Lock: sha1:MTn6hsKyI53hV+5p5TykYOp2ulk= In-Reply-To: Bytes: 4012 On Fri, 2025-03-14 at 10:51 -0500, olcott wrote: > On 3/14/2025 10:04 AM, wij wrote: > > On Fri, 2025-03-14 at 09:35 -0500, olcott wrote:>> > > > void DDD() > > > { > > > =C2=A0=C2=A0=C2=A0 HHH(DDD); > > > =C2=A0=C2=A0=C2=A0 return; > > > } > > >=20 > > > DDD correctly simulated by HHH cannot possibly reach > > > its own "return" instruction in any finite number of > > > correctly simulated steps. > > >=20 > > > That you are clueless about the semantics of something > > > as simple as a tiny C function proves that you are not > > > competent to review my work. > > >=20 > >=20 > > https://en.wikipedia.org/wiki/Halting_problem > > In computability theory, the halting problem is the problem of determin= ing, from a description of > > an > > arbitrary computer program and an input, whether the program will finis= h running, or continue to > > run > > forever. > >=20 > > That means: H(D)=3D1 if D() halts and H(D)=3D0 if D() does not halt. > >=20 > > But, it seems you don't understand English, as least as my level, .... > >=20 > >=20 > >=20 >=20 > void DDD() > { > =C2=A0=C2=A0 HHH(DDD); > =C2=A0=C2=A0 return; > } >=20 > The only difference between HHH and HHH1 is that they are > at different locations in memory. DDD simulated by HHH1 > has identical behavior to DDD() directly executed in main(). >=20 > The semantics of the finite string input DDD to HHH specifies > that it will continue to call HHH(DDD) in recursive simulation. >=20 > The semantics of the finite string input DDD to HHH1 specifies > to simulate to DDD exactly once. >=20 > When HHH(DDD) reports on the behavior that its input finite > string specifies it can only correctly report non-halting. >=20 > When HHH(DDD) is required to report on behavior other than > the behavior that its finite string specifies HHH is not > a decider thus not a halt decider. >=20 > All deciders are required to compute the mapping from > their input finite string to the semantic or syntactic property > that this string specifies. Deciders return true when this > string specifies this property otherwise they return false. >=20 Are you solving The Halting Problem or not? Yes or No.