This book constitutes the refereed proceedings of the 23rd International Conference on Principles and Practice of Multi-Agent Systems, PRIMA 2020, held in hybrid mode in Valencia, Spain, in November 2022. The 31 full papers presented together with 15 short papers and 1 demo paper were carefully reviewed and selected from 100 submissions.The conference covers a wide range of ranging from foundations of agent theory and engineering aspects of agent systems, to emerging interdisciplinary areas of agent-based research.

This book constitutes thoroughly revised selected papers of the Second International Workshop on Conflict and Resolution in Decision Makrung, COREDEMA 2016, held in The Hague, The Netherlands, in August 2016. The 9 revised papers presented were carefully reviewed and selected from 13 submissions. The 2nd International Workshop on Conflict Resolution in Decision Making (COREDEMA 2016) focuses on theoretical and practical computational approaches for solving and understanding conflict resolution.