No CrossRef data available.
Published online by Cambridge University Press: 12 March 2014
In [1], Lemmon provides us with his now well-known formulations of the Lewis-modal systems S1 through S4. This paper will present similar bases for the related systems S1° and S2° of Feys [2], and S3° and S4° of Sobocinski [3]. Notation and definitions here will be as in [1]. Standard bases for the Lewis-modal systems may be drawn from the following stock of axioms and rules, as is done in [1].