On products of elementarily indivisible structures
Abstract
We say a structure in a first-order language is indivisible if for every coloring of its universe in two colors, there is a monochromatic substructure of such that is isomorphic to . Additionally, we say that is symmetrically indivisible if can be chosen to be symmetrically embedded in (that is, every automorphism of can be extended to an automorphism of ). Similarly, we say that is elementarily indivisible if can be chosen to be an elementary substructure. We define new products of structures in a relational language. We use these products to give recipes for construction of elementarily indivisible structures which are not transitive and elementarily indivisible structures which are not symmetrically indivisible, answering two questions presented by A. Hasson, M. Kojman and A. Onshuus.
Keywords
Cite
@article{arxiv.1502.00897,
title = {On products of elementarily indivisible structures},
author = {Nadav Meir},
journal= {arXiv preprint arXiv:1502.00897},
year = {2019}
}
Comments
21 pages, minor corrections