Untranscendable order types
Combinatorics
2026-03-02 v1 Logic
Abstract
We introduce and study a multiplicative analogue of additive indecomposability for linear order types that we call untranscendability, as well as a strengthening that we call -untranscendability. We show that, with the unique exception of the two-point type, every untranscendable type is additively indecomposable, and every -scattered untranscendable type is strongly indecomposable. Under the Proper Forcing Axiom, every untranscendable Aronszajn type is strongly indecomposable. We also show that a theorem of Hagendorf and Jullien, that every strictly additively indecomposable type must be strictly indecomposable to either the left or right, has a natural analogue for -untranscendable types.
Cite
@article{arxiv.2602.24285,
title = {Untranscendable order types},
author = {Garrett Ervin and Alberto Marcone and Thilo Weinert},
journal= {arXiv preprint arXiv:2602.24285},
year = {2026}
}