English

General non-structure theory and constructing from linear orders

Logic 2023-05-19 v2

Abstract

The theme of the first two sections, is to prepare the framework of how from a ``complicated'' family of so called index models IK1I \in K_1 we build many and/or complicated structures in a class K2K_2. The index models are characteristically linear orders, trees with κ+1\kappa+1 levels (possibly with linear order on the set of successors of a member) and linearly ordered graphs; for this we formulate relevant complicatedness properties (called bigness). In the third section we show stronger results concerning linear orders. If for each linear order II of cardinality λ>0\lambda > \aleph_0 we can attach a model MIKλM_I \in K_\lambda in which the linear order can be embedded such that for enough cuts of II, their being omitted is reflected in MIM_I, then there are 2λ2^\lambda non-isomorphic cases. We also do the work for some applications.

Keywords

Cite

@article{arxiv.2305.02003,
  title  = {General non-structure theory and constructing from linear orders},
  author = {Saharon Shelah},
  journal= {arXiv preprint arXiv:2305.02003},
  year   = {2023}
}

Comments

This was mistakenly submitted as new rather than an update of arXiv:1011.3576

R2 v1 2026-06-28T10:24:22.776Z