Abstract
In this paper we attempt to shed light on the concept
of an agent’s knowledge after a non-deterministic
action is executed. We start by making a comparison between notions of non-deterministic choice,
and between notions of sequential composition, of
settings with dynamic and/or epistemic character;
namely Propositional Dynamic Logic (PDL), Dynamic Epistemic Logic (DEL), and the more recent
logic of Semi-Public Environments (SPE). These logics represent two different approaches for defining
the aforementioned actions, and in order to provide
unified frameworks that encompass both, we define
the logics DELVO (DEL+Vision+Ontic change) and
PDLVE (PDL+Vision+Epistemic operators). DELVO is
given a sound and complete axiomatisation