 As a general convention, a multimodal language with modalities \(\Box_1\), …, \(\Box_n\), … will be denoted by \(\mathcal{L}^{f(\Box_1),\ldots, f(\Box_n),\ldots}\), where the function \(f\) associates to each modality its intuitive shorthand. Let \(\Delta\) be a modal language consisting of modalities \(\Box_1\), …, \(\Box_n\), … and let \(M = ((W, R_1, \ldots, R_n, \ldots), V )\) be a model for this language. The satisfaction relation of a formula \(\varphi \in \Delta\) with respect to a pair \((M,w)\), where \(w \in W\), is defined according to the following truth conditions: