Path: ...!weretis.net!feeder9.news.weretis.net!i2pn.org!i2pn2.org!.POSTED!not-for-mail From: joes Newsgroups: comp.theory,sci.logic Subject: Re: Simulating termination analyzers by dummies --- What does halting mean? Date: Tue, 18 Jun 2024 17:57:14 -0000 (UTC) Organization: i2pn2 (i2pn.org) Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Tue, 18 Jun 2024 17:57:14 -0000 (UTC) Injection-Info: i2pn2.org; logging-data="404894"; mail-complaints-to="usenet@i2pn2.org"; posting-account="nS1KMHaUuWOnF/ukOJzx6Ssd8y16q9UPs1GZ+I3D0CM"; User-Agent: Pan/0.145 (Duplicitous mercenary valetism; d7e168a git.gnome.org/pan2) X-Spam-Checker-Version: SpamAssassin 4.0.0 Bytes: 2253 Lines: 24 Am Tue, 18 Jun 2024 12:25:44 -0500 schrieb olcott: > On 6/18/2024 12:06 PM, joes wrote: > void DDD() > { > H0(DDD); > } > DDD correctly simulated by any H0 cannot possibly halt. >> DDD halts iff H0 halts. So H0 returns "doesn't halt" to DDD, which then stops running, so H0 should have returned "halts". > Some TM's loop and thus never stop running, this is classical > non-halting behavior. UTM's simulate Turing machine descriptions. > This is the same thing as an interpreter interpreting the source-code of > a program. Some TMs do not loop and do not halt. > A UTM can be adapted so that it only simulates a fixed number of > iterations of an input that loops. When this UTM stops simulating this > Turing machine description we cannot correctly say that this looping > input halted. Yes. We also cannot say that that input was simulated correctly. -- joes