Coalitions in Epistemic Planning
Suzanne van Wijk

Abstract:
The aim of this thesis is to augment dynamic epistemic logic and its framework in order to model planning problems where coalitions of agents try to reach a given goal. We add an additional control relation to the static epistemic models and action models of DEL, similar to choice equivalence in stit logics, thereby enabling us to represent the power of coalitions while keeping the means to talk about specific actions. We then introduce a sound, complete and decidable logic for these augmented models, which can express knowledge, distributed knowledge and both past and future control of coalitions, and we demonstrate how this can be used for coalitional planning.
We then add common knowledge to the logic, in order to model the coordination of agents within a coalition: indeed, common knowledge enables agents to trust the other coalition members to perform the right action. As reduction axioms cannot be found for common knowledge, we show soundness, completeness and decidability for our enriched version of epistemic PDL, where we take as basic programs group indistinguishability relations rather than single agent indistinguishability.
Finally, the thesis proposes a way in which agents can commit to certain actions, providing them with a way to communicate their plans and coordinate, thereby greatly improving their possibilities for achieving their goal.