Tangent circle graphs and ‘orders’

Autor: Philippe Vincke, Marc Pirlot, Moncef Abbas
Rok vydání: 2007
Předmět:
Zdroj: Discrete Applied Mathematics. 155(4):429-441
ISSN: 0166-218X
DOI: 10.1016/j.dam.2006.09.004
Popis: Consider a horizontal line in the plane and let @c(A) be a collection of n circles, possibly of different sizes all tangent to the line on the same side. We define the tangent circle graph associated to @c(A) as the intersection graph of the circles. We also define an irreflexive and asymmetric binary relation P on A; the pair (a,b) representing two circles of @c(A) is in P iff the circle associated to a lies to the right of the circle associated to b and does not intersect it. This defines a new nontransitive preference structure that generalizes the semi-order structure. We study its properties and relationships with other well-known order structures, provide a numerical representation and establish a sufficient condition implying that P is transitive. The tangent circle preference structure offers a geometric interpretation of a model of preference relations defined by means of a numerical representation with multiplicative threshold; this representation has appeared in several recently published papers.
Databáze: OpenAIRE