 As mentioned above, “structural rules” may refer to two things: either to the standard dialogical structural rules presented in Section 2, or, as it is here the case, to rules imported from another framework (which would be called “strategic” rules in the standard framework). In the BIO approach, Prover can thus produce sequents that follow from others in virtue of rules such as contraction or weakening. The aim of this kind of dialogical approach is to understand the “structural” properties of deduction.