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From: Aatu Koskensilta on 8 Aug 2010 16:54 Newberry <newberryxy(a)gmail.com> writes: > This sentence: > > ~(Ex)(Ey)(Pxy & Qy). (3.3.1) > > Pxy means that x is the proof of y, where x and y are G�del numbers of > wffs or sequences of wffs. Q has been constructed such that only one y > = m satisfies it, and m is the G�del number of (3.3.1). Proof in what theory? -- Aatu Koskensilta (aatu.koskensilta(a)uta.fi) "Wovon man nicht sprechen kann, dar�ber muss man schweigen" - Ludwig Wittgenstein, Tractatus Logico-Philosophicus
From: Newberry on 8 Aug 2010 20:56 On Aug 8, 1:54 pm, Aatu Koskensilta <aatu.koskensi...(a)uta.fi> wrote: > Newberry <newberr...(a)gmail.com> writes: > > This sentence: > > > ~(Ex)(Ey)(Pxy & Qy). (3.3.1) > > > Pxy means that x is the proof of y, where x and y are Gödel numbers of > > wffs or sequences of wffs. Q has been constructed such that only one y > > = m satisfies it, and m is the Gödel number of (3.3.1). > > Proof in what theory? How does it matter?
From: Don Stockbauer on 8 Aug 2010 21:01 On Aug 8, 7:56 pm, Newberry <newberr...(a)gmail.com> wrote: > On Aug 8, 1:54 pm, Aatu Koskensilta <aatu.koskensi...(a)uta.fi> wrote: > > > Newberry <newberr...(a)gmail.com> writes: > > > This sentence: > > > > ~(Ex)(Ey)(Pxy & Qy). (3.3.1) > > > > Pxy means that x is the proof of y, where x and y are Gödel numbers of > > > wffs or sequences of wffs. Q has been constructed such that only one y > > > = m satisfies it, and m is the Gödel number of (3.3.1). > > > Proof in what theory? > > How does it matter? Does any of this put food on the table?
From: Newberry on 9 Aug 2010 09:29 On Aug 9, 5:24 am, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: > In article <6b4407fe-f953-48eb-a22c-f9ab8de85...(a)g6g2000pro.googlegroups.com>, > Newberry says... > > > > >On Aug 8, 1:54=A0pm, Aatu Koskensilta <aatu.koskensi...(a)uta.fi> wrote: > >> Newberry <newberr...(a)gmail.com> writes: > >> > This sentence: > > >> > =A0 =A0 ~(Ex)(Ey)(Pxy & Qy). =A0 =A0 =A0 (3.3.1) > > >> > Pxy means that x is the proof of y, where x and y are G=F6del numbers o= > >f > >> > wffs or sequences of wffs. Q has been constructed such that only one y > >> > =3D m satisfies it, and m is the G=F6del number of (3.3.1). > > >> Proof in what theory? > > >How does it matter? > > If it doesn't matter, then why would you object to my assuming that we > are talking about PA? > > I've run rings around you, logically. Hahahaha. The question was what is Goedel sentence. The formula I exhibited is Goedel's formula in many kinds of logic including PA. If we take PA to be purely syntactic then we can re-interpret the formula. But if we want a sound system it is obviously not going to be PA. > -- > Daryl McCullough > Ithaca, Ny
From: Newberry on 9 Aug 2010 10:22
On Aug 9, 6:33 am, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: > Newberry says... > > >The question was what is Goedel sentence. The formula I exhibited is > >Goedel's formula in many kinds of logic including PA. > > If it is sufficiently similar to the Godel formula for PA, then it > is nonsensical to say that it is neither true nor false. Would you care to define "sufficiently similar" and show how your conclusion follows? |