Title
Ramsey-type numbers involving graphs and hypergraphs with large girth.
Abstract
For a set of integers S, define (SAPk) to be the k-uniform hypergraph with vertex set S and hyperedges corresponding the set of all arithmetic progression of length k in S. Similarly, for a graph H, define (HKk) to be the (k2)-uniform hypergaph on the vertex ser E(H) with hyperedges corresponding to the edge sets of all copies of Kk in H. Also, we say that a k-uniform hypergraph has girth at least g if any h edges (1≤h<g) span at least (k−1)h+1 vertices. For all integers k and ℓ, we establish the existence of a relatively small graph H having girth k and the property that every ℓ-coloring of the edges of H yields a monochromatic copy of Ck. We also show that for all integers k,ℓ, and g, there exists a relatively small set S⊂N such that the related hypergraph (SAPk) had girth g and each ℓ-colorings of S yields a monochromatic arithmetic progression of length k. Finally, for all integers k,ℓ, and g, we establish the existence of a relatively small graph H such that the associated hypergraph (HKk) has girth g and each ℓ-coloring of the edges of H yields a monochromatic copy of Kk. Our proofs give improved (and the first explicit) numerical bounds on the size of these objects.
Year
DOI
Venue
2015
10.1016/j.endm.2015.07.076
Electronic Notes in Discrete Mathematics
Field
DocType
Volume
Integer,Discrete mathematics,Graph,Combinatorics,Monochromatic color,Vertex (geometry),Constraint graph,Ramsey's theorem,Mathematics
Journal
50
ISSN
Citations 
PageRank 
1571-0653
0
0.34
References 
Authors
7
4
Name
Order
Citations
PageRank
Hiêp Hàn1398.07
Troy Retter252.20
Vojtech Rödl3877139.49
Mathias Schacht436137.90