 If one combines all these new values into a joint framework, one obtains the four-valued logic \(B_4\) introduced by Dunn and Belnap (Dunn 1976; Belnap 1977a,b). A Gentzen-style formulation can be found in Font (1997: 7)). This logic is determined by the Belnap matrix \(\mathbf{B}_4 = \langle \{\mathbf{N}, \mathbf{T}, \mathbf{F}, \mathbf{B}\}, \{\mathbf{T}, \mathbf{B}\}, \{ f_c: c \in \{\sim , \wedge , \vee \}\}\rangle\), where the functions \(f_c\) are defined as follows: