Paper List

Journal: ArXiv Preprint
Published: 2026-03-19
Game TheoryComputational Biology

Evolutionarily Stable Stackelberg Equilibrium

Ganzfried Research

Sam Ganzfried

30-Second Overview

IN SHORT: Bridges the gap between Stackelberg leadership models and evolutionary stability by requiring follower strategies to be robust against mutant invasions.

Key Novelties

  • Methodology Introduces the first formal integration of Stackelberg equilibrium with evolutionary stability, creating the SESS concept.
  • Methodology Develops computational algorithms for both discrete normal-form games and continuous-trait games, enabling practical application.
  • Biology Provides a natural framework for modeling asymmetric interactions in biological systems, such as physician-cancer cell dynamics in treatment optimization.

Conclusions

  • The SESS framework successfully refines Stackelberg equilibrium by restricting follower responses to evolutionarily stable strategies (ESS), ensuring robustness against mutant invasions.
  • Computational complexity analysis indicates that determining ESS existence is Σ₂ᴾ-complete, significantly harder than computing Nash equilibrium, highlighting the added value of stability guarantees.
  • The model provides a direct and natural application to cancer treatment optimization, where the physician (leader) optimizes treatment against a population of cancer cell phenotypes (followers) that evolve stably.
Research Gap: Existing Stackelberg evolutionary game models either rely on evolutionary dynamics for follower response or assume rational best-response behavior, but fail to explicitly enforce the crucial biological property of stability against invasion by mutant strategies, which is central to evolutionary game theory.

Abstract: We present a new solution concept called evolutionarily stable Stackelberg equilibrium (SESS). We study the Stackelberg evolutionary game setting in which there is a single leading player and a symmetric population of followers. The leader selects an optimal mixed strategy, anticipating that the follower population plays an evolutionarily stable strategy (ESS) in the induced subgame and may satisfy additional ecological conditions. We consider both leader-optimal and follower-optimal selection among ESSs, which arise as special cases of our framework. Prior approaches to Stackelberg evolutionary games either define the follower response via evolutionary dynamics or assume rational best-response behavior, without explicitly enforcing stability against invasion by mutations. We present algorithms for computing SESS in discrete and continuous games, and validate the latter empirically. Our model applies naturally to biological settings; for example, in cancer treatment the leader represents the physician and the followers correspond to competing cancer cell phenotypes.