• Corpus ID: 215814106

On first order amenability

@article{Hrushovski2020OnFO,
  title={On first order amenability},
  author={Ehud Hrushovski and Krzysztof Krupinski and Anand Pillay},
  journal={arXiv: Logic},
  year={2020}
}
We introduce the notion of first order [extreme] amenability, as a property of a first order theory $T$: every complete type over $\emptyset$, in possibly infinitely many variables, extends to an automorphism-invariant global Keisler measure [type] in the same variables. [Extreme] amenability of $T$ will follow from [extreme] amenability of the (topological) group $Aut(M)$ for all sufficiently large $\aleph_{0}$-homogeneous countable models $M$ of $T$ (assuming $T$ to be countable), but is… 

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