Runtime Analysis of Evolutionary Algorithms for Multi-party Multi-objective Optimization

TL;DR

This paper provides a theoretical analysis of evolutionary algorithms for multi-party multi-objective optimization, highlighting inefficiencies of traditional methods and proposing new algorithms with improved runtime and solution consensus.

Contribution

It introduces the first theoretical runtime analysis for bi-party multi-objective problems and proposes novel EMPMO algorithms for pseudo-Boolean and shortest path problems.

Findings

Traditional algorithms are inefficient for MPMOPs.

Proposed EMPMO algorithms outperform previous methods.

Consensus-based EMPMO achieves better efficiency and accuracy.

Abstract

In scenarios where multiple decision-makers operate within a common decision space, each focusing on their own multi-objective optimization problem (e.g., bargaining games), the problem can be modeled as a multi-party multi-objective optimization problem (MPMOP). While numerous evolutionary algorithms have been proposed to solve MPMOPs, most results remain empirical. This paper presents the first theoretical analysis of the expected runtime of evolutionary algorithms on bi-party multi-objective optimization problems (BPMOPs). Our findings demonstrate that employing traditional multi-objective optimization algorithms to solve MPMOPs is both time-consuming and inefficient, as the resulting population contains many solutions that fail to achieve consensus among decision-makers. An alternative approach involves decision-makers individually solving their respective optimization problems and seeking consensus only in the final stage. While feasible for pseudo-Boolean optimization problems, this method may fail to guarantee approximate performance for one party in NP-hard problems. Finally, we propose evolutionary multi-party multi-objective optimizers (EMPMO) for pseudo-Boolean optimization and shortest path problems within a multi-party multi-objective context, maintain a common solution set among all parties. Theoretical and experimental results demonstrate that the proposed \( \text{EMPMO}_{\text{random}} \) outperforms previous algorithms in terms of the lower bound on the expected runtime for pseudo-Boolean optimization problems. Additionally, the consensus-based evolutionary multi-party multi-objective optimizer( \( \text{EMPMO}_{\text{cons}}^{\text{SP}} \) ) achieves better efficiency and precision in solving shortest path problems compared to existing algorithms.