Bercher, PascalBartak, RomanOndrckova, SimonaBehnke, GregorBienvenu, MeghynLakemeyer, GerhardErdem, Esra2023-07-24November 3978-1-956792-99-7http://hdl.handle.net/1885/294519Hierarchical task network (HTN) planning is a model-based approach to planning. The HTN domain model consists of tasks and methods to decompose them into subtasks until obtaining primitive tasks (actions). There are recent methods for verifying if a given action sequence is a valid HTN plan. However, if the plan is invalid, all existing verification methods only say so without explaining why the plan is invalid. In the paper, we propose a method that corrects a given action sequence to form a valid HTN plan by deleting the minimal number of actions. This plan correction explains what is wrong with a given action sequence concerning the HTN domain model.This research was partially supported by TAILOR, a project funded by EU Horizon 2020 research and innovation programme under GA No 952215, and by the joint Czech-German project registered under the number 21-13882J by the Czech Science Foundation (GACR) and BE 7458/1-1 by Deutsche Forschungsgemeinschaft (DFG). Simona Ondrckova is (partially) supported by SVV project number 260575.application/pdfen-AU© 2021 International Joint Conferences on Artificial Intelligence OrganizationExplanation findingdiagnosiscausal reasoningabduction Reasoning about actions and changeaction languages Reasoning about constraintsconstraint programming Explainable AI202110.24963/kr.2021/102022-05-22