Modal systems in which necessity is ``factorable''.

Which Modal Logic Is the Right One?

The question, “Which modal logic is the right one for logical necessity?,” divides into two questions, one about model-theoretic validity, the other about proof-theoretic demonstrability. The arguments of Halldén and others that the right validity argument is S5, and the right demonstrability logic includes S4, are reviewed, and certain common objections are argued to be fallacious. A new argum...

Which classical correspondence is valid in intuitionistic modal logic?

Modal logics reason about properties of relational structures, and such properties are often characterized by axioms of modal logics. This connection between properties of relational structures and axioms of modal logics are called correspondence, and has been investigated well in the classical setting. The problem we consider is an intuitionistic version of this correspondence. In particular, ...

Which is which and who is who: Roger Waters up against Media

Pink Floyd was a British band whose work began in the late 60s. Roger Waters, the main contributor of the band, wrote almost all the lyrics and was also a main figure behind producing the motion picture of the album. He deliberately attacks Western media in both the lyrics he has written for the band and his solo projects. The present study finds this tendency of assaulting the media deeply roo...

Hilbert algebras with a necessity modal operator

Received 12 December 2013 1991 Mathematics Subject Classification: 03G25; 06D05

Animal Rights Consideration is a Necessity in Conducting an Experiment