Abstract
We study a high-dimensional analog for the notion of an acyclic (aka transitive) tournament. We give upper and lower bounds on the number of d-dimensional n-vertex acyclic tournaments. In addition, we prove that every n-vertex d-dimensional tournament contains an acyclic subtournament of Ω(log1/d n) vertices and the bound is tight. This statement for tournaments (i.e., the case d = 1) is a well-known fact. We indicate a connection between acyclic high-dimensional tournaments and Ramsey numbers of hypergraphs.We investigate aswell the inter-relations among various other notions of acyclicity in high-dimensional tournaments. These include combinatorial, geometric and topological concepts.
Original language | English |
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Pages (from-to) | 1085-1100 |
Number of pages | 16 |
Journal | Discrete and Computational Geometry |
Volume | 50 |
Issue number | 4 |
DOIs | |
State | Published - Dec 2013 |
Bibliographical note
Funding Information:We were not sure for a while which of the many notions of acyclicity would be of greatest interest to study. We are grateful to Roy Meshulam for helping us take the (hopefully) right decision. Research supported in part by the Israel Science Foundation and by a USA–Israel BSF Grant
Keywords
- Acyclic
- Enumeration
- High-dimensional
- Hyper-plane arrangements
- Tournament