Classical propositional logic plays a prominent role in industrial applications, and yet the complexity of this logic is presumed to be non-feasible. Tractable systems such as depth-bounded boolean logics approximate classical logic and can be seen as a model for resource-bounded agents whose reasoning style is nonetheless classical. In this paper we first study a hierarchy of tractable logics that is not defined by depth. Then we extend it into a modal logic where modalities make explicit the assumptions discharged in (...) propositional proofs, thereby expressing blueprints for proofs. A natural deduction system is provided that permits to reason about and manage such proof blueprints. (shrink)

We consider the propositional logic equipped with Chellas stit operators for a finite set of individual agents plus the historical necessity modality. We settle the question of whether such a logic enjoys restricted interpolation property, which requires the existence of an interpolant only in cases where the consequence contains no Chellas stit operators occurring in the premise. We show that if action operators count as logical symbols, then such a logic has restricted interpolation property iff the number of agents does (...) not exceed three. On the other hand, if action operators are considered to be nonlogical symbols, then the restricted interpolation fails for any number of agents exceeding one. It follows that unrestricted Craig interpolation also fails for almost all versions of stit logic. (shrink)

In Part I of this paper we presented a Hilbert-style system $\Sigma _D$ axiomatizing stit logic of justification announcements interpreted over models with discrete time structure. In this part, we prove three frame definability results for $\Sigma _D$ using three different definitions of a frame plus another version of completeness result.

The article aims to determine how university professors critically perceive and evaluate information when interacting with the media sphere. The study's relevance is due to the insufficient elaboration of Russian teachers' attitude to the information in the media sphere, which is significant in developing students' critical thinking. The study analyzes theoretical sources and documents on critical thinking in the media sphere and the results of processing empirical data obtained from questioning teachers. The main measuring instrument is a questionnaire survey of (...) university professors with various lengths of service. The study involved 76 teachers from Ural Federal University named after the first President of Russia B.N. Yeltsin. Ural State Pedagogical University (Ekaterinburg, Russia). Linguistics University of Nizhny Novgorod (Nizhny Novgorod, Russia). The data obtained from the study of the teachers' attitude to the information content of the media sphere show a predominant critical attitude in assessing the reliability and availability of information on social networking platforms. This conclusion is important for personality traits that develop students' critical thinking. (shrink)