Many symmetrically indivisible structures
Abstract
A structure in a first-order language is \emph{indivisible} if for every coloring of in two colors, there is a monochromatic such that . Additionally, we say that is symmetrically indivisible if can be chosen to be \emph{symmetrically embedded} in (that is, every automorphism of can be extended to an automorphism of ). In the following paper we give a general method for constructing new symmetrically indivisible structures out of existing ones. Using this method, we construct many non-isomorphic symmetrically indivisible countable structures in given (elementary) classes and answer negatively the following question asked by A. Hasson, M. Kojman and A. Onshuus in "On symmetric indivisibility of countable structures" (Cont. Math. 558(1):453--466): Let be a symmetrically indivisible structure in a language . Let . Is symmetrically indivisible?
Keywords
Cite
@article{arxiv.1411.1202,
title = {Many symmetrically indivisible structures},
author = {Nadav Meir},
journal= {arXiv preprint arXiv:1411.1202},
year = {2019}
}
Comments
10 pages