Abstract
We use κ-free but not Whitehead Abelian groups to construct Abstract Elementary Classes (AEC) which satisfy the amalgamation property but fail various conditions on the locality of Galois-types. We introduce the notion that an AEC admits intersections. We conclude that for AEC which admit intersections, the amalgamation property can have no positive effect on locality: there is a transformation of AEC's which preserves non-locality but takes any AEC which admits intersections to one with amalgamation. More specifically we have: Theorem 5.3. There is an AEC with amalgamation which is not (N0, N1)-tame but is (2N0, ∞)-tame; Theorem 3.3. It is consistent with ZFC that there is an AEC with amalgamation which is not (≤ N2, ≤ N2-compact.
| Original language | English |
|---|---|
| Pages (from-to) | 765-782 |
| Number of pages | 18 |
| Journal | Journal of Symbolic Logic |
| Volume | 73 |
| Issue number | 3 |
| DOIs | |
| State | Published - Sep 2008 |
| Externally published | Yes |
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