%0 Journal Article %A Arlo-Costa, Horacio %D 2001 %T First Order Extensions of Classical Systems of Modal Logic: The Role of the Barcan Schemas %U https://kilthub.cmu.edu/articles/journal_contribution/First_Order_Extensions_of_Classical_Systems_of_Modal_Logic_The_Role_of_the_Barcan_Schemas/6491585 %R 10.1184/R1/6491585.v1 %2 https://kilthub.cmu.edu/ndownloader/files/11934500 %K First order modal logic %K Epistemic logic %K Barcan forumlas %K Logic of likelihood %X The paper studies first order extensions of classical systems of modal logic (see (Chellas, 1980, part III)). We focus on the role of the Barcan formulas. It is shown that these formulas correspond to fundamental properties of neighborhood frames. %I Carnegie Mellon University