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- Newsgroups: sci.math
- Path: sparky!uunet!snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!triples.math.mcgill.ca!boshuck
- From: boshuck@triples.math.mcgill.ca (William Boshuck)
- Subject: Re: Expansion of set theory
- Message-ID: <1992Aug13.174408.10574@thunder.mcrcim.mcgill.edu>
- Sender: news@thunder.mcrcim.mcgill.edu
- Nntp-Posting-Host: triples.math.mcgill.ca
- Organization: Dept Of Mathematics and Statistics
- References: <1992Aug7.002122.24601@access.usask.ca> <1992Aug12.164408.10547@thunder.mcrcim.mcgill.edu> <1992Aug12.182912.4659@sics.se>
- Date: Thu, 13 Aug 92 17:44:08 GMT
- Lines: 34
-
- In article <1992Aug12.182912.4659@sics.se> torkel@sics.se (Torkel Franzen) writes:
- >In article <1992Aug12.164408.10547@thunder.mcrcim.mcgill.edu> boshuck@triples.
- >math.mcgill.ca (William Boshuck) writes:
- >
- > >An intersting facet of all of this is that large cardinal axioms
- > >actually have a bearing on relatively small things, like Borel
- > >sets of real numbers, and sets of natural numbers in the definable
- > >hierarchy.
- >
- > And, it should be added, on the natural numbers themselves (in the form
- >of theorems concerning the unsolvability of Diophantine equations).
-
- I think that this is included in my remark about sets in the
- definable hierarchy. That is, the solvability or not of
- Diophantine equations is a question in what might be called
- the definability theory of Sigma^0_1 sets. On the other
- hand, I don't quite know what theorems you may be talking
- about. A big theorem in this area, that there is no uniform
- algorithm to decide whether a given Diophantine equation has
- solutions (due to Matiesevitz (spelling?) I think) doesn't
- use any aspects of the theory of large cardinals (an easy
- presentation of this theorem can be found in Bell and
- Machover's book on mathematical logic).
-
- Maybe you want to contribute a more complete post on this
- matter. One of the things I am looking forward to learning
- is this sort of interaction between the unumaginably large
- and facts about the natural numbers. I would appreciate
- hearing whatever you may have to say on the matter.
-
- WHB
-
-
-