Speaker: Fernando R. Velázquez Quesada (ILLC, Amsterdam)
Date and Time: Friday, November 11th 2016, 15:30-17:00
Venue: ILLC Seminar Room F1.15, Science Park 107.
Title: Reliability-based preference change: lexicographic upgrade.
Abstract: This work studies a particular method through which individuals might change their preferences according not only to what one another prefers, but also to a reliability ordering each one of them assigns to the group. More precisely, we consider agents that have not only a preference ordering over a set of objects, but also a reliability ordering over the agents themselves; then we study the effects of the public and simultaneous announcement of these individual preferences by defining an operation, the lexicographic upgrade, which receives a collection of preference relations plus a ‘priority’ ordering among them, and returns a preference relation. We will review alternative definitions of this lexicographic upgrade, depending on the properties of the priority ordering, and present a sound and complete axiom system for a language describing this operation’s effects. Time permitting, we will also discuss the effects of the iterative application of this upgrade, focusing in particular on the cases in which preference unanimity can be reached.