Abstract

In his paper, ìRight Weakening and Right Contraction in LK î, Hirokawa investigates the properties of the structural rules of contraction and weak- ening as they appear in a certain sequent calculus formulation of Örst order classical logic. In what follows we explore the notion of correspondence, in particular with reference to the structural rules in the succedent, and in doing so critically examine the sensitivity of Hirokawaís results to the formulation of the calculus, both with respect to the formulations of the rules governing the connectives present and to the choice of the connectives themselves.