Title
Large Bd-free and union-free subfamilies.
Abstract
For a property Γ and a family of sets F, let f(F,Γ) be the size of the largest subfamily of F having property Γ. For a positive integer m, let f(m,Γ) be the minimum of f(F,Γ) over all families of size m. A family F is said to be Bd-free if it has no subfamily F′={FI:I⊆[d]} of 2d distinct sets such that for every I,J⊆[d], both FI∪FJ=FI∪J and FI∩FJ=FI∩J hold. A family F is a-union free if F1∪⋯∪Fa≠Fa+1 whenever F1,…,Fa+1 are distinct sets in F. We verify a conjecture of Erdős and Shelah that f(m,B2-free)=Θ(m2/3). We also obtain lower and upper bounds for f(m,Bd-free) and f(m,a-union free).
Year
DOI
Venue
2012
10.1016/j.endm.2011.09.017
Electronic Notes in Discrete Mathematics
Keywords
DocType
Volume
extremal set theory,union-free subfamilies,Bd-free subfamilies
Journal
38
Issue
ISSN
Citations 
1
1571-0653
0
PageRank 
References 
Authors
0.34
2
5
Name
Order
Citations
PageRank
János Barát114114.18
Zoltán Füredi21237233.60
Ida Kantor362.76
Younjin Kim472.64
Balázs Patkós58521.60