Disjoint Amalgamation in Locally Finite AEC

نویسندگان

  • John T. Baldwin
  • Martin Koerwien
  • Michael C. Laskowski
چکیده

We introduce the concept of a locally finite abstract elementary class and develop the theory of excellence (with respect to disjoint ( , k)-amalgamation) for such classes. From this we find a family of complete L!1,! sentences r that a) homogeneously characterizes @r (improving results of Hjorth [12] and Laskowski-Shelah [14] and answering a question of [22]), while b) the r provide the first examples of a class of models of a complete sentence in L!1,! where the spectrum of cardinals in which amalgamation holds is other that none or all.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Hanf Numbers and Presentation Theorems in AEC

Grossberg [Gro02, Conjecture 9.3] has raised the question of the existence of Hanf numbers for joint embedding and amalgamation in Abstract Elementary Classes (AEC). Various authors have given lower bounds (discussed in Section 5), usually for the disjoint version of these properties. Here we show a strongly compact cardinal κ is an upper bound for various such Hanf numbers. We define 4 kinds a...

متن کامل

Uniqueness of limit models in classes with amalgamation

We prove: Theorem 0.1 (Main Theorem). Let K be an AEC and μ > LS(K). Suppose K satisfies the disjoint amalgamation property for models of cardinality μ. If K is μ-Galois-stable, does not have long splitting chains, and satisfies locality of splitting, then any two (μ, σl)-limits over M for (l ∈ {1, 2}) are isomorphic over M . This result extends results of Shelah from [Sh 394], [Sh 576], [Sh 60...

متن کامل

On pm$^+$ and finite character bi-amalgamation

‎Let $f:Arightarrow B$ and $g:A rightarrow C$ be two ring homomorphisms and let $J$ and $J^{'}$ be two ideals of $B$ and $C$‎, ‎respectively‎, ‎such that $f^{-1}(J)=g^{-1}(J^{'})$‎. ‎The bi-amalgamation of $A$ with $(B,C)$ along $(J,J^{'})$ with respect of $(f,g)$ is the subring of $Btimes C$ given by‎ ‎$Abowtie^{f,g}(J,J^{'})={(f(a)+j,g(a)+j^{'})‎/ ‎a in A‎, ‎(j,j^{'}) in Jtimes J^{'}}.$‎ ‎In ...

متن کامل

Examples of non-locality

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...

متن کامل

Downward categoricity from a successor inside a good frame

We use orthogonality calculus to prove a downward transfer from categoricity in a successor in abstract elementary classes (AECs) that have a good frame (a forking-like notion for types of singletons) on an interval of cardinals: Theorem 0.1. Let K be an AEC and let LS(K) ≤ λ < θ be cardinals. If K has a type-full good [λ, θ]-frame and K is categorical in both λ and θ, then K is categorical in ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • J. Symb. Log.

دوره 82  شماره 

صفحات  -

تاریخ انتشار 2017