The Thousands of Problems for Theorem Provers (TPTP) World is a well-established infrastructure that supports research, development and deployment of automated theorem proving systems. This paper provides an overview of the logic languages of the TPTP World, from classical first-order form (FOF), through typed FOF, up to typed higher-order form, and beyond to non-classical forms. The logic languages are described in a non-technical way and are illustrated with examples using the TPTP language.

The paper is devoted to the concise description of some Natural Deduction System (ND for short) for Linear Temporal Logic. The system's distinctive feature is that it is labelled and analytical. Labels convey necessary semantic information connected with the rules for temporal functors while the analytical character of the rules lets the system work as a decision procedure. It makes it more similar to Labelled Tableau Systems than to standard Natural Deduction. In fact, our solution of linearity representation is rather (...) independent of the underlying proof method, provided that some form of (analytic) cut is admissible. We will also discuss some generalisations of the system and compare it with other formalizations of linearity. (shrink)