Term Definable Classes of Boolean Functions and Frame Definability in Modal Logic.

Miguel Couceiro Lauri Hella Jari Kivelä Term Definable Classes of Boolean Functions and Frame Definability in Modal Logic. 43-73 2008 16 Logic Journal of the IGPL 1 http://dx.doi.org/10.1093/jigpal/jzm018 db/journals/igpl/igpl16.html#CouceiroHK08