Path: csiph.com!eternal-september.org!feeder.eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail From: Ben Bacarisse Newsgroups: comp.theory Subject: Re: Simply defining =?iso-8859-1?Q?G=F6del?= Incompleteness and Tarski Undefinability away V33 (Mendelson Satisfiability) Date: Tue, 28 Jul 2020 03:11:15 +0100 Organization: A noiseless patient Spider Lines: 52 Message-ID: <87wo2ocrss.fsf@bsb.me.uk> References: <87lfjfovhm.fsf@bsb.me.uk> <87zh7tok63.fsf@bsb.me.uk> <6MednYs8F9v7qYvCnZ2dnUU7-R3NnZ2d@giganews.com> <87lfjcmg9p.fsf@bsb.me.uk> <87tuxzkswv.fsf@bsb.me.uk> <87zh7ojzp8.fsf@bsb.me.uk> <877dusjsda.fsf@bsb.me.uk> <87zh7mgiux.fsf@bsb.me.uk> <877duphmxf.fsf@bsb.me.uk> <87blk1f6er.fsf@bsb.me.uk> <87tuxseg31.fsf@bsb.me.uk> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: reader02.eternal-september.org; posting-host="b47480b175bc26dbdce6ab6dc8aa44b1"; logging-data="25803"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+Gyc0KITTWXU/5UUKW/FI4KUKkn2Te74I=" Cancel-Lock: sha1:XQ8Lg/sn8gmHlEeewK1hFmRgM4E= sha1:pVTU/uvhcA+MctlzTrL5GITUMpE= X-BSB-Auth: 1.684bce4443258eca91b4.20200728031115BST.87wo2ocrss.fsf@bsb.me.uk Xref: csiph.com comp.theory:21972 olcott writes: > On 7/27/2020 5:41 PM, Ben Bacarisse wrote: >> olcott writes: >> >>> On 7/27/2020 8:12 AM, Ben Bacarisse wrote: >>>> olcott writes: >> >>>>> Thus Father_of(a26, a87) would be Boolean where a26, a87 are in the >>>>> Domain of Humans. >>>> >>>> I'm going to stop commenting on this sort of issue. You won't say what >>>> Father_of is and you won't even say what language you are using. >>>> Mendelson uses 'a' with a subscript for constants in a formal language, >>>> but you talk of a26 and a87 as being "in the domain" (with a capital >>>> letter for some reason). I just don't have time to try to unravel what >>>> you mean. It's possible that even you don't know if Father_of is a >>>> predicate or a function symbol in the formal language, or a >>>> corresponding relation or function in some interpretation of it. >>> >>> You can' possibly imagine that I a referring to the exactly same >>> context as Mendelson unless I always copy his whole page 57 ? >> >> (a) I don't sit here with Mendelson open at page 57 (it's 58 in my very >> old edition). >> >> (b) You changed the name so if I /was/ looking at Mendelson I would >> assume you were referring to something different. >> >> (c) You write a26 and a87 which Mendelson uses for constants in a >> language and therefore make no sense in the context to his 'father of' >> relation. >> >> So get off your high-horse and make yourself understood. I won't keep >> trying to work out what you mean. You tell me what you mean. By all >> means use the same terms, syntax and wording as Mendelson, but you will >> need to know how to use them correctly. >> >> I still have no idea what you mean by "Father_of(a26, a87) would be >> Boolean". If you mean what Mendelson talks about as 'father of' it is a >> set of pairs. A subset of DxD. Boolean (whatever you mean by that in >> this context) does not come into it. >> > For a particular ordered pair of individual humans the first > individual human either is the father_of the second one or not. > > I don't see why this is so difficult for you. It is not. That is why I advise you to use words. -- Ben.