Title
On diamond-free subposets of the Boolean lattice
Abstract
The Boolean lattice of dimension two, also known as the diamond, consists of four distinct elements with the following property: A@?B,C@?D. A diamond-free family in the n-dimensional Boolean lattice is a subposet such that no four elements form a diamond. Note that elements B and C may or may not be related. There is a diamond-free family in the n-dimensional Boolean lattice of size (2-o(1))(n@?n/2@?). In this paper, we prove that any diamond-free family in the n-dimensional Boolean lattice has size at most (2.25+o(1))(n@?n/2@?). Furthermore, we show that the so-called Lubell function of a diamond-free family in the n-dimensional Boolean lattice which contains the empty set is at most 2.25+o(1), which is asymptotically best possible.
Year
DOI
Venue
2013
10.1016/j.jcta.2012.11.002
J. Comb. Theory, Ser. A
Keywords
Field
DocType
distinct element,elements b,empty set,following property,n-dimensional boolean lattice,diamond-free subposets,boolean lattice,so-called lubell function,diamond-free family
Diamond,Discrete mathematics,Empty set,Combinatorics,Boolean algebra (structure),Mathematics
Journal
Volume
Issue
ISSN
120
3
0097-3165
Citations 
PageRank 
References 
15
0.89
8
Authors
3
Name
Order
Citations
PageRank
Lucas Kramer1151.57
Ryan R. Martin23610.12
Michael Young3495.07