Sahlqvist Correspondence for Modal mu-calculus

We define analogues of modal Sahlqvist formulas for the modal mu-calculus, and prove a correspondence theorem for them.     

Logic Games are Complete for Game Logics

Game logics describe general games through powers of players for forcing outcomes. In particular, they encode an algebra of sequential game operations such as choice, dual and composition. Logic games are special games for specific purposes such as proof or semantical evaluation for first-order or modal languages. We show that the general algebra of game operations coincides with that over just logical evaluation games, whence the latter are quite general after all. The main tool in proving this is a representation of arbitrary games as modal or first-order evaluation games. We probe how far our analysis extends to product operations on games. We also discuss some more general consequences of this new perspective for standard logic.     

编者导言(英文)

This special issue of the journal‘Studies in Logic’ results from an international workshopon‘TheHistory of Logic in China’held in Amsterdam,The Netherlands,on November 24-26, 2010 (http://www.sciencehistory.asia/history-logic-china).This event brought together,     

The many faces of interpolation

We present a number of, somewhat unusual, ways of describing what Craig’s interpolation theorem achieves, and use them to identify some open problems and further directions.