The system KE+, a tableau-like proof system based on D'Agostino-Mondadori KE, is presented in this paper. This system avoids some of the drawbacks of other proof methods. In fact it is completely analytical, it is able to detect whether a formula is either a tautology or a contradiction or only a satisfiable one; in the course of a proof it can detect whether a subformula is a tautology and it uses this fact in the proof of the main formula
