Ladders and Squares
Logic
2025-12-01 v2 Combinatorics
Abstract
In 1984, Ditor asked two questions: (1) For each and infinite cardinal , is there a join-semilattice of breadth and cardinality whose principal ideals have cardinality ? (2) For each , is there a lower-finite lattice of cardinality whose elements have at most lower covers? We show that both questions have positive answers under the axiom of constructibility, and hence consistently with . More specifically, we derive the positive answers from assuming that holds for enough 's.
Keywords
Cite
@article{arxiv.2505.00414,
title = {Ladders and Squares},
author = {Lorenzo Notaro},
journal= {arXiv preprint arXiv:2505.00414},
year = {2025}
}
Comments
30 pages