 In order to provide a better explanation of this technique, here we will discuss the construction of a simple temporal epistemic logic. On the epistemic side, recall that the basic  epistemic logic  system is given, syntactically, by the language \(\cL_{\left\{ K \right\}}\), and semantically, by a relational model. In it, the modality K is semantically interpreted in terms of a binary relation \(R_K\). On the temporal side, define the ‘future’ fragment of the basic  temporal (tense) logic  as a system which is syntactically specified by the language \(\cL_{\left\{ G \right\}}\) (with G a universal quantification on the future, and F its existential counterpart given by \(F\varphi := \lnot G\lnot \varphi)\), and semantically, by a relational model with \(R_G\) as the crucial relation.