# First-order justification logic JT45

## Felipe Salvatore

### University of São Paulo

Among the different propositional justification logics, JT45 is the justification counterpart of the modal logic S5. Although there is a growing literature about propositional justification logic, there are only a few papers about the first-order version of justification logic. And most of those papers focus on the first-order version of LP. The goal of this talk is to present a first approach to first-order JT45 (FOJT45). Using Fitting models we will present a possible worlds semantics for FOJT45 and with that establish a Completeness Theorem. We will also discuss some topics related to first-order modal logic such as the Barcan Formula and the failure of the Interpolation Theorem.

Felipe Salvatore is a graduate student in philosophy at University of São Paulo interested in modal logic, epistemology and philosophy of language.