Title
Union-intersecting set systems
Abstract
Three intersection theorems are proved. First, we determine the size of the largest set system, where the system of the pairwise unions is $$l$$l-intersecting. Then we investigate set systems where the union of any $$s$$s sets intersect the union of any $$t$$t sets. The maximal size of such a set system is determined exactly if $$s+t\\le 4$$s+t≤4, and asymptotically if $$s+t\\ge 5$$s+t¿5. Finally, we exactly determine the maximal size of a $$k$$k-uniform set system that has the above described $$(s,t)$$(s,t)-union-intersecting property, for large enough $$n$$n.
Year
DOI
Venue
2015
10.1007/s00373-014-1456-7
Graphs and Combinatorics
Keywords
Field
DocType
Extremal set systems, Intersecting family, Erdős-Ko-Rado theorem, $$\Delta $$Δ-system, Forbidden subposets, 05D05
Discrete mathematics,Pairwise comparison,Combinatorics,Erdős–Ko–Rado theorem,Mathematics,The Intersect
Journal
Volume
Issue
ISSN
31
5
1435-5914
Citations 
PageRank 
References 
2
0.43
4
Authors
2
Name
Order
Citations
PageRank
Gyula O. H. Katona126466.44
Dániel T. Nagy231.19