Some problems with two axiomatizations of discussive logic

Abstract

Problems in two axiomatizations of Jaśkowski's discussive (or discursive) logic D2 are considered. A recent axiomatization of D2 and completeness proof relative to D2's intended semantics seems to be mistaken because some formulas valid according to the intended semantics turn out to be unprovable. Although no new axiomatization is offered, nor a repaired completeness proof given, the shortcomings identified here may be a step toward an improved axiomatization.

13 pages. Submitted to Trends in Logic XIII 2014