 We will call this basic language that includes both a Knowledge and a Belief operator, \(\mathcal{L}_{KB}\). As in propositional logic, additional connectives are defined from \(\neg\) and \(\wedge\): Typical notation is ‘\(\vee\)’ for ‘or’, ‘\(\rightarrow\)’ for ‘if…, then …’ and ‘\(\leftrightarrow\)’ for ‘… if, and only if, …’. Also typically \(\top\) (‘top’) and \(\bot\) (‘bottom’) is used to denote the constantly true proposition and the constantly false proposition, respectively.