Hostname: page-component-74656f9884-2dmjx Total loading time: 0 Render date: 2026-11-09T15:06:14.112Z Has data issue: false hasContentIssue false

Finding an Unknown Acyclic Orientation of a Given Graph

Published online by Cambridge University Press:  09 July 2009

OLEG PIKHURKO*
Affiliation:
Department of Mathematical Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA (web: http://www.math.cmu.edu/~pikhurko)
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the 'Save PDF' action button.

Let c(G) be the smallest number of edges we have to test in order to determine an unknown acyclic orientation of the given graph G in the worst case. For example, if G is the complete graph on n vertices, then c(G) is the smallest number of comparisons needed to sort n numbers.

We prove that c(G) ≤ (1/4 + o(1))n2 for any graph G on n vertices, answering in the affirmative a question of Aigner, Triesch and Tuza [Discrete Mathematics144 (1995) 3–10]. Also, we show that, for every ϵ > 0, it is NP-hard to approximate the parameter c(G) within a multiplicative factor 74/73 − ϵ.

Information

Type
Paper
Copyright
Copyright © Cambridge University Press 2009