On large externally definable sets in NIP
We study cofinal systems of finite subsets of ω1. We show that while such systems can be NIP, they cannot be defined in an NIP structure. We deduce a positive answer to a question of Chernikov and Simon from 2013: in an NIP theory, any uncountable externally definable set contains an infinite defina...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
Cambridge University Press
2023
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