@techreport{TR-DCC-93-27,
number = {DCC-93-27},
author = {Meidanis, João},
title = {A Unified Characterization of Chordal, Interval, Indifference, and Other Classes of Graphs},
month = {September},
year = {1993},
institution = {Department of Computer Science, University of Campinas},
note = {In English, 17 pages.
\par\selectlanguage{english}\textbf{Abstract}
Motivated by very similar characterizations given in the
literature for chordal, interval, and indifference graphs we
introduce a way of defining classes of graphs in terms of boolean
functions of two variables. Each such function originates a class
of graphs. Denoting the variables by ${\bf 1}$ and ${\bf 2}$, the
functions ${\bf 1}\Rightarrow{\bf 2}$, ${\bf 1}$, and ${\bf
1}\wedge{\bf 2}$ originate the classes of chordal, interval, and
indifference graphs, respectively. In this paper we study the
classes corresponding to all other boolean functions, as well as
general properties of these classes. A satisfactory
identification of the class corresponding to function ${\bf
1}\oplus{\bf 2}$ (exclusive or) is still open.
}
}