In the matter of arbitration, the principle of due process, laid down by art. 101 cod. proc. civ. and referred to by art. 829 co. 1 n. 9 cod. proc. civ. as a ground of nullity of the arbitral award, has a substantive connotation, so that for the purposes of a declaration of nullity it is necessary to ascertain the actual impairment of the right of defence, having regard to the manner in which the parties were confronted and to the possibilities afforded to them of exercising on a footing of equality the procedural faculties attributed to them.
In the matter of arbitration, the application of art. 1227 cod. civ. by the arbitrators of their own motion, understood as the legal characterisation of the facts, does not violate the principle of due process where the parties have been placed in a position to make submissions on the facts which, though supplementary to the breach, were relied upon as the basis of the decision.
The sanction of nullity provided for by art. 829 co. 1 n. 4 cod. proc. civ. in respect of an arbitral award containing contradictory provisions does not correspond to that of art. 360 co. 1 n. 5 cod. proc. civ., but is to be understood in the sense that such contradiction must appear between the several components of the operative part, or between the reasoning and the operative part, whereas an internal contradiction between the several parts of the reasoning, not expressly included among the defects entailing the nullity of the arbitral award, may assume relevance as a defect of the award only in so far as it renders it absolutely impossible to reconstruct the logical and legal reasoning underlying the decision by reason of the total absence of reasoning referable to its functional model.