The Strategy-Proofness Landscape of Merging

TL;DR

This paper explores the strategy-proofness of various belief merging operators, analyzing their susceptibility to manipulation and identifying conditions under which they are resistant to strategic lying.

Contribution

It provides a comprehensive analysis of the strategy-proofness landscape for multiple merging operators, including both model-based and formula-based approaches.

Findings

Identifies which merging operators are strategy-proof under different conditions.

Maps the landscape of manipulability for various merging techniques.

Highlights restrictions that enhance strategy-proofness.

Abstract

Merging operators aim at defining the beliefs/goals of a group of agents from the beliefs/goals of each member of the group. Whenever an agent of the group has preferences over the possible results of the merging process (i.e., the possible merged bases), she can try to rig the merging process by lying on her true beliefs/goals if this leads to better merged base according to her point of view. Obviously, strategy-proof operators are highly desirable in order to guarantee equity among agents even when some of them are not sincere. In this paper, we draw the strategy-proof landscape for many merging operators from the literature, including model-based ones and formula-based ones. Both the general case and several restrictions on the merging process are considered.