Uniform Agent-interpolation of Distributed Knowledge

Abstract: Uniform interpolation property (UIP) is a strengthening of Craig interpolation property. It can be understood as the definability of propositional quantifiers. This paper develops the sequent calculi provided in Murai and Sano (2020), combining with the methods studied by B{\'ı}lkov{á} (2007) to show the uniform interpolation for epistemic logic $\mathbf{K}$, $\mathbf{KD}$ and $\mathbf{KT}$ with distributed knowledge. A purely syntactic algorithm is presented to determine a uniform interpolant formula. In the definition of an interpolant formula, not only propositional variables but also agent symbols are taken into consideration.