| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4656738 | Journal of Combinatorial Theory, Series B | 2015 | 21 Pages |
Abstract
We introduce a new method to construct uncountably chromatic graphs from non-special trees and ladder systems. Answering a question of P. Erdős and A. Hajnal from 1985, we construct graphs of chromatic number ω1ω1 without uncountable ω -connected subgraphs. Second, we build triangle free graphs of chromatic number ω1ω1 without subgraphs isomorphic to Hω,ω+2Hω,ω+2.
Keywords
Related Topics
Physical Sciences and Engineering
Mathematics
Discrete Mathematics and Combinatorics
Authors
Dániel T. Soukup,