Challenge of an award for nullity under Article 829 of the Code of Civil Procedure has a limited character, admitted only to assert errors in law (errores in iudicando) and procedural errors (errores in procedendo) within the boundaries of the aforesaid provision. It does not enable the challenge court to re-examine the arbitral decision on its merits, but permits exclusively rescinding judgment (iudicium rescindens).
Following the reform of Article 829(3) of the Code of Civil Procedure effected by Legislative Decree 40/2006, challenge for violation of rules of law relating to the merits of the dispute is admitted only if expressly provided by the parties or by law, with consequent reversal of the previous approach which always admitted such challenge save different agreement.
Defect of reasoning in an arbitral award, being a defect referable to Article 829(5) of the Code of Civil Procedure, is detectable only when reasoning is entirely absent or so deficient as not to permit identification of the ratio of the decision adopted, denoting an argumentative process absolutely unacceptable on the dialectical plane.
In arbitral proceedings, the question of violation of adversarial procedure must be examined not from a formal perspective but within the ambit of an inquiry aimed at ascertaining effective prejudice to the possibility of pleading and contradicting, requiring specific indication of the harm caused to the right of defence.
For purposes of Article 829(3) of the Code of Civil Procedure, contrariety to public policy must be interpreted restrictively as reference limited to fundamental and mandatory norms of the legal system, requiring that the award contain in its operative part a command in clear contrast with principles founding the legal order.
Contradiction in an award under Article 829(1)(11) of the Code of Civil Procedure is relevant when the conflict emerges between different components of the operative part or between reasoning and operative part, whilst internal contradiction between different parts of the reasoning does not constitute an autonomous defect.