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arXiv · 2004.02125

On the number of independent orders

Kota Takeuchi·Akito Tsuboi
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Abstract

We investigate a model theoretic invariant $κ_{srd}^m(T)$, which was introduced by Shelah in his famous book, and prove that $κ_{srd}^m(T)$ is sub-additive. When $κ_{srd}^m(T)$ is infinite, this gives the equality $κ^m_{srd}(T)=κ^1_{srd}(T)$, answering a question by Shelah. We apply the same proof method to analyze another invariant $κ^m_{ird}(T)$, and show that it is also sub-additive, improving a result in the book.

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Kota Takeuchi, Akito Tsuboi. 2020-04-05. On the number of independent orders. https://arxiv.org/abs/2004.02125

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