“…Concrete case studies we have undertaken with MetTeL 2 include implementing unlabelled tableau calculi for Boolean logic and three-valued Lukasiewicz logic, labelled tableau calculi for standard modal logics K, KT, S4, description logic ALCO, a hybrid logic K(E n ) with global counting operators [19], a multi-agent interrogative epistemic logic [21], and internalised tableau calculi for hybrid and description logics. We used MetTeL 2 to implement a tableau decision procedure for ALBO id , a description logic with the same expressive power as the two-variable fragment of first-order logic.…”