Continuum Without Non-Block Points
Abstract
For any composant and corresponding near-coherence class we prove the following are equivalent : (1) properly contains a dense semicontinuum. (2) Each countable subset of is contained in a dense proper semicontinuum of . (3) Each countable subset of is disjoint from some dense proper semicontinuum of . (4) has a minimal element in the finite-to-one monotone order of ultrafilters. (5) has a -point. A consequence is that NCF is equivalent to containing no proper dense semicontinuum and no non-block points. This gives an axiom-contingent answer to a question of the author. Thus every known continuum has either a proper dense semicontinuum at every point or at no points. We examine the structure of indecomposable continua for which this fails, and deduce they contain a maximum semicontinuum with dense interior.
Keywords
Cite
@article{arxiv.2007.09168,
title = {Continuum Without Non-Block Points},
author = {Daron Anderson},
journal= {arXiv preprint arXiv:2007.09168},
year = {2020}
}