Core Concepts
The core message of this article is to develop a logical framework, called the Logic of Dependence with Temporalized Variables (LDTV), for reasoning about dependencies that manifest over time in dynamical systems. The authors introduce this logic, provide a complete axiomatization, and show that its satisfiability problem is decidable.
Abstract
The article introduces the Logic of Dependence with Temporalized Variables (LDTV) to study temporal dependencies in dynamical systems. The key highlights are:
LDTV combines a modal logic of static functional dependence (LFD) with temporal vocabulary to capture how future values of variables depend on earlier ones.
The authors show that LDTV is decidable by reducing it to the decidable logic LFDf, which extends LFD with function symbols.
A complete Hilbert-style proof system for LDTV is provided, demonstrating that the logic is also finitely axiomatizable.
The authors then extend LDTV to LDTVf,≡by adding function symbols and global term identity. Decidability and completeness are again established for this richer logic.
Moving closer to standard temporal logics, the authors analyze the intuition that future truth about variable values is the same as current truth about future values. They identify the structural conditions on dynamical systems needed for this intuition to hold, leading to the logic LTDt,f,≡.
Finally, the authors introduce a more general temporal dependence logic LTD for arbitrary dynamical systems, prove its decidability and completeness, using a more complex modal filtration-based approach.