## Section: Partnerships and Cooperations

### International Initiatives

#### Participation in Other International Programs

##### PHC Amadeus: Analytic Calculi for Modal Logics

Participants : Kaustuv Chaudhuri, Sonia Marin, Giselle Reis, Lutz Straßburger.

Modal logics are obtained from propositional logics by adding modalities $\square $ and $\diamond $, meaning necessity and possibility. Originally studied by philosophers in order to reason about knowledge and belief, modal logics have nowadays many applications in computer science. Well known examples are epistemic logics, which allow to formally reason about the knowledge of independently acting and interacting agents, temporal logics, which allow to reason about temporal properties of processes, and authentication logics, which are used to formally reason about authentication protocols.

The purpose of this project is to develop a proof theory for variants of modal logic that have applications in modern computer science but that have been neglected by traditional proof theory so far.