A note on the Erd\H{o}s-Szekeres theorem in two dimensions
Abstract
Burkill and Mirsky, and Kalmanson, prove independently that, for every , there is a sequence of vectors in , which does not contain a subsequence of vectors such that, for every between 1 and , forms a monotone sequence. Moreover, is the largest integer with this property. In this short note, for two vectors and in , we say that if, for every between 1 and , . Just like Burkill and Mirsky, and Kalmanson, for every we find the maximal (which turn out to be equal) such that there are numerical two-dimensional arrays of size and , which neither contain a subarray of size , whose columns form a non-decreasing sequence of vectors in , nor contain a subarray of size , whose columns form a non-increasing sequence of vectors in . In a consequent discussion, we consider a generalisation of this setting and make a connection with a famous problem in coding theory.
Keywords
Cite
@article{arxiv.2009.08164,
title = {A note on the Erd\H{o}s-Szekeres theorem in two dimensions},
author = {Lyuben Lichev},
journal= {arXiv preprint arXiv:2009.08164},
year = {2021}
}
Comments
6 pages, 1 figure. In the second version, the upper bound on M_2(n) in the second remark after Theorem 2.1 was corrected. In the third version, minor corrections were introduced