 The fusion of these systems is syntactically specified by the language \(\cL_{\left\{ K, G \right\}}\) (i.e., a language freely generated by the union of the modalities of \(\cL_{\left\{ K \right\}}\) and \(\cL_{\left\{ G \right\}})\). Formulas of this language are semantically interpreted in relational models of the form \({\langle W, R_K, R_G, V \rangle}\) such that \({\langle W, R_K, V \rangle}\) is a model for \(\cL_{\left\{ K \right\}}\) and \({\langle W, R_G, V \rangle}\) is a model for \(\cL_{\left\{ G \right\}}\). For the semantic interpretation, formulas of the new language are interpreted in the standard way, with each modality using its correspondent relation. With respect to axiom systems, it is enough to put together those of the individual logics.