 Formulas \([a]F\) are assigned a reading that is doxastic (“agent a believes F”) or epistemic (“agent a knows F”), with the particular reading depending on the application one has in mind. In this article we will use both readings interchangeably, choosing whichever is more convenient in a given context. In the language \eqref{ML}, Boolean connectives other than negation \(\lnot\) and conjunction \(\land\) are taken as abbreviations in terms of negation in conjunction as is familiar from any elementary Logic textbook. See  Appendix A  for further details on \eqref{ML} and its Kripke semantics. 