  In order to turn this into a semantics of the logical constants of propositional logic, von Kutschera argues as follows: When giving up bivalence, we can no longer use classical truth-value assignments to atomic formulas. Instead we can use calculi which prove or refute atomic sentences. Moreover, since calculi not only generate proofs or refutations but arbitrary derivability relations, the idea is to start directly with derivability in an atomic system and extend it with rules that characterize the logical connectives. For that von Kutschera gives a sequent calculus with rules for the introduction of n-ary propositional connectives in the succedent and antecedent, yielding a sequent system for generalized propositional connectives. Von Kutschera then goes on to show that the generalized connectives so defined can all be expressed by the standard connectives of intuitionistic logic (conjunction, disjunction, implication, absurdity).