Copy and remove as dynamic operators

Abstract

In this article, we present a modal logic that extends the basic modal logic ML with two dynamic operators: copy (cp), which replicates the current model, labelling each copy with a different propositional symbol and respecting accessibility relations even between distinct copies; and remove (rm), which deletes paths in the model that satisfy certain intermediate conditions. We call the resulting logic ML(cp,rm). We study its computational complexity, and its relative expressivity with respect to (static) modal logics ML and ML(□−), and the dynamic epistemic Action Model Logic, AML.