Sievers, S., Röger, G., Wehrle, M. and Katz, M. 2021. Theoretical Foundations for Structural Symmetries of Lifted PDDL Tasks. Proceedings of the International Conference on Automated Planning and Scheduling. 29, 1 (May 2021), 446-454. DOI:https://doi.org/10.1609/icaps.v29i1.3509.