Modal Logic
in [Logic]
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From: Khodaeifar on 30 Sep 2006 06:46 "Barb Knox" <see(a)sig.below> wrote in message news:see-577E28.17254530092006(a)lust.ihug.co.nz... > In article <efki7v$lg0$3(a)emma.aioe.org>, > "Khodaeifar" <khodaeifar(a)gmail.com> wrote: > >> Hi all, >> Is there anybody interested in "Modal Logic" ? >> I need a debater! >> Thanks > > Modal Logic is a rather well understood technical area. What do you > find debatable? > > [added sci.logic] ====================================== Well, why the systems in "classical modal logic" have been not modeled by a method similar to Kripke method?
From: Confutus on 3 Oct 2006 22:12 I'm interested, but I have a radically unorthodox approach to the subject. A number of years ago I worked out how a modal logic formally similar to the Lewis system S5 could be based on Lukasiewicz 3-valued logic, and I haven't yet been able to find anyone much interested in it. Khodaeifar wrote: > Hi all, > Is there anybody interested in "Modal Logic" ? > I need a debater! > Thanks
From: Jan Burse on 4 Oct 2006 12:04 There are two names around. Some logics are called modal, and some logics are called multi valued. It can be shown that modal logics correspond with certain infinitely valued logics. But on the other hand it can also be shown that finitly valued logics do not correspond with certain modal logics. So that is why some logics are called modal and other are called 3-valued, and they do not correspond to each other. If you want a reference on my claims, please let me know. There have also already been posts in this news group that support this claim. Bye Confutus wrote: > I'm interested, but I have a radically unorthodox approach to the > subject. A number of years ago I worked out how a modal logic formally > similar to the Lewis system S5 could be based on Lukasiewicz 3-valued > logic, and I haven't yet been able to find anyone much interested in > it. > > Khodaeifar wrote: > >>Hi all, >>Is there anybody interested in "Modal Logic" ? >>I need a debater! >>Thanks > >
From: Confutus on 4 Oct 2006 18:26 Yes, I have studied the literature I could find, and I'm familiar with the huge gulf between multi-valued logics and modal logics and the reasons, both logical and historical for it. I also know that modal logics and multivalued logics *as they have been developed* are different and incompatible. What I have is a development of 3-valued logic that looks and acts very like one of the Lewis systems and their many, many, descendants and kindred, until you look at it closely and see just how unrelated it is. Jan Burse wrote: > There are two names around. Some logics > are called modal, and some logics are > called multi valued. > > It can be shown that modal logics correspond > with certain infinitely valued logics. > But on the other hand it can also be shown > that finitly valued logics do not correspond > with certain modal logics. > > So that is why some logics are called modal > and other are called 3-valued, and they > do not correspond to each other. > > If you want a reference on my claims, > please let me know. There have also already > been posts in this news group that support > this claim. > > Bye >
From: Confutus on 5 Oct 2006 06:47
> > Sure, S5 is not n valued for finite n, but the op says _similar_ to the > Lewis system S5. Didn't Lukasiewicz have a four-valued modal logic? > Iirc it's in his North-Holland collected papers and Prior discusses it > somewhere. > I believe he did. IIRC it was more or less discarded as unworkable. I ran across it when I was studying his 3-valued system, and it didn't work for my purposes at the time, either, but I did make a mental note of it. Now that I've worked out the difficulties with the 3-valued version, I'd like to go back and take another look, and see if it can be salvaged, but the references are not so readily available to me now. |