Double threshold orders: a new axiomatization

The paper presents some new results concerning the axiomatization of double threshold preference structures. Such structures, which have been introduced in order to model a situation of hesitation between the strict preference and the indifference, were not axiomatized through the use of a single characteristic relation. We give two theorems for this purpose, exploiting a four valued logic recently introduced by the authors as a preference modeling language under hesitation. © 1998 John Wiley & Sons, Ltd.