Tameness, uniqueness triples and amalgamation

Adi Jarden

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

We combine two approaches to the study of classification theory of AECs:. (1)that of Shelah: studying non-forking frames without assuming the amalgamation property but assuming the existence of uniqueness triples and(2)that of Grossberg and VanDieren [6]: (studying non-splitting) assuming the amalgamation property and tameness.In [7] we derive a good non-forking λ+-frame from a semi-good non-forking λ-frame. But the classes Kλ++ and {precedes above singleline equals sign}{up harpoon right} Kλ++ are replaced: Kλ++ is restricted to the saturated models and the partial order {precedes above singleline equals sign}{up harpoon right}Kλ++ is restricted to the partial order {precedes above singleline equals sign}λ+NF.Here, we avoid the restriction of the partial order {precedes above singleline equals sign}{up harpoon right}Kλ++, assuming that every saturated model (in λ+ over λ) is an amalgamation base and (λ, λ+)-tameness for non-forking types over saturated models (in addition to the hypotheses of [7]): Theorem 7.15 states that M{precedes above singleline equals sign}M+ if and only if M{precedes above singleline equals sign}λ+NFM+, provided that M and M+ are saturated models.We present sufficient conditions for three good non-forking λ+-frames: one relates to all the models of cardinality λ+ and the two others relate to the saturated models only. By an 'unproven claim' of Shelah, if we can repeat this procedure ω times, namely, 'derive' good non-forking λ+n frame for each n<ω then the categoricity conjecture holds.In [14], Vasey applies Theorem 7.8, proving the categoricity conjecture under the above 'unproven claim' of Shelah.In [10], we apply Theorem 7.15, proving the existence of primeness triples.

Original languageEnglish
Pages (from-to)155-188
Number of pages34
JournalAnnals of Pure and Applied Logic
Volume167
Issue number2
DOIs
StatePublished - Feb 2016

Keywords

  • Abstract elementary classes
  • Amalgamation
  • Categoricity
  • Frames
  • Tameness
  • Uniqueness triples

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