On Middle Grounds for Preference Statements
On Middle Grounds for Preference Statements
Anne-Marie George, Ana Ozaki
Proceedings of the Thirty-Fourth International Joint Conference on Artificial Intelligence
Main Track. Pages 4518-4525.
https://doi.org/10.24963/ijcai.2025/503
In group decisions or deliberations, stakeholders are often confronted with conflicting opinions. We investigate a logic-based way of expressing such opinions and a formal general notion of a middle ground between stakeholders. Inspired by the literature on preferences with hierarchical and lexicographic models, we instantiate our general framework to the case where stakeholders express their opinions using preference statements of the form ‘I prefer ‘a’ to ‘b’’, where ‘a’ and ‘b’ are alternatives expressed over some attributes, e.g., in a trolley problem, one can express I prefer to save 1 adult and 1 child to 2 adults (and 0 children). We prove theoretical results on the existence and uniqueness of middle grounds. In particular, we show that, for preference statements, middle grounds may not exist and may not be unique. We provide algorithms for deciding the existence and finding middle grounds.
Keywords:
Knowledge Representation and Reasoning: KRR: Preference modelling and preference-based reasoning
Game Theory and Economic Paradigms: GTEP: Computational social choice
Knowledge Representation and Reasoning: KRR: Reasoning about knowledge and belief
