Modal: First-Order Modal Sequent Calculus

This directory contains the Standard ML sources of the Isabelle system for Modal Logic. Important files include
ROOT.ML
loads all source files. Enter an ML image containing LK Isabelle and type: use "ROOT.ML";

ex
subdirectory containing examples. Files Tthms.ML, S4thms.ML and S43thms.ML contain the theorems of Modal Logics, so arranged since T<S4<S43. To execute them, enter an ML image containing Modal and type: use "ex/ROOT.ML";
Thanks to Rajeev Gore' for supplying the inference system for S43.

Useful references on Modal Logics: