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Re: Complete types

Subject: Re: Complete types
From: "galathaea"
Date: 6 Aug 2006 10:45:12 -0700
Newsgroups: sci.logic
Blake Manner wrote:
> Is it true that for any two elements of some L-structure A realizing
> the same complete type, there is an automorphism of A swapping those
> two elements, and fixing all the rest of A?

this seems almost immediate

the automoprhisms are those f:A->A
  that preserve all definable relations

the complete types are those collections
  of definable relations
  maximal over the formulae on its elements

so
  if two elements realise the same complete type
  all definable relations between those elements
    and the rest of the structure
  do not differ
and the swap mapping is automorphic

am i missing a technicality?

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galathaea: prankster, fablist, magician, liar


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