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Failed to connect to MySQL: (1203) User howardkn already has more than 'max_user_connections' active connectionsPath: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: olcott Newsgroups: comp.theory Subject: Re: How to write a self-referencial TM? Date: Wed, 14 May 2025 12:45:41 -0500 Organization: A noiseless patient Spider Lines: 41 Message-ID: <1002ks5$2kb74$1@dont-email.me> References: <1e4f1a15826e67e7faf7a3c2104d09e9dadc6f06.camel@gmail.com> <1002akp$2i4bk$2@dont-email.me> <479eebef3bd93e82c8fe363908b254b11d15a799.camel@gmail.com> <1002jkk$2k00a$3@dont-email.me> <3730ad28e597073892c1ab23233df671d82e2b8a.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Wed, 14 May 2025 19:45:42 +0200 (CEST) Injection-Info: dont-email.me; posting-host="1b4c815c0318038d25de37dcdc1ad225"; logging-data="2764004"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+4QOKxZ8U3ijXQoTdHasxz" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:B3JiqVgZGVUm4EZFckckBfsjLWs= X-Antivirus-Status: Clean In-Reply-To: <3730ad28e597073892c1ab23233df671d82e2b8a.camel@gmail.com> X-Antivirus: Norton (VPS 250514-4, 5/14/2025), Outbound message Content-Language: en-US Bytes: 2537 On 5/14/2025 12:39 PM, wij wrote: > On Wed, 2025-05-14 at 12:24 -0500, olcott wrote: >> On 5/14/2025 11:43 AM, wij wrote: >>> On Wed, 2025-05-14 at 09:51 -0500, olcott wrote: >>>> On 5/14/2025 12:13 AM, wij wrote: >>>>> Q: Write a turing machine that performs D function (which calls itself): >>>>> >>>>> void D() { >>>>>    D(); >>>>> } >>>>> >>>>> Easy? >>>>> >>>>> >>>> >>>> That is not a TM. >>> >>> It is a C program that exists. Therefore, there must be a equivalent TM. >>> >>>> To make a TM that references itself the closest >>>> thing is a UTM that simulates its own TM source-code. >>> >>> How does a UTM simulate its own TM source-code? >>> >> >> You run a UTM that has its own source-code on its tape. > > What is exactly UTM? https://en.wikipedia.org/wiki/Universal_Turing_machine > E.g. can the HHH in POOH or x86utm reads its own source-code? > As I have said many dozens of times and Mike affirmed HHH does emulate itself emulating DDD. It does this through direct access to its own x86 machine language. -- Copyright 2025 Olcott "Talent hits a target no one else can hit; Genius hits a target no one else can see." Arthur Schopenhauer