PreprintarXiv licencearXiv
Forking in monadically NIP theories
Abstract
We demonstrate that forking in monadically NIP theories satisfies a very strong form of triviality over arbitrary sets, generalizing Baldwin-Shelah in monadically stable theories and analogous to Shelah's result for finite satisfiability over models in monadically NIP theories. This implies in particular that strict non-forking independence is particularly well behaved, and that the forking relation induces a canonical semilinear partial order on singletons. We also give an example of an ω-categorical monadically NIP theory so that no finite set is an extension base.
Related
BibTeX
@misc{chernikov2026forking,
title = {{Forking in monadically NIP theories}},
author = {Artem Chernikov},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.25068},
eprint = {2609.25068},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.25068},
}
RIS
TY - UNPB
TI - Forking in monadically NIP theories
AU - Artem Chernikov
PY - 2026
DA - 2026/09/17
PB - arXiv
DO - 10.48550/arxiv.2609.25068
UR - https://arxiv.org/abs/2609.25068
AB - We demonstrate that forking in monadically NIP theories satisfies a very strong form of triviality over arbitrary sets, generalizing Baldwin-Shelah in monadically stable theories and analogous to Shelah's result for finite satisfiability over models in monadically NIP theories. This implies in particular that strict non-forking independence is particularly well behaved, and that the forking relation induces a canonical semilinear partial order on singletons. We also give an example of an ω-categorical monadically NIP theory so that no finite set is an extension base.
ER -