It was my initial idea, but then I realized that we have far more folders that allows parent inheritance, then disallow, so we may end up significalty more number of relations in the database. Another part of concern its performance impact of intersection operator. As I understand if I follow via enable boolean attribute, I need to make something like

permission read = (parent->read & parent_inheritance_enabled) + viewer + editor

, right? In this case, does intersection force to solve the entire set, while exclision operator may work on the same performance as union operator?