The assessment of the facts pleaded and of the evidence obtained in the arbitral proceedings cannot be challenged by way of an application for the nullity of the arbitral award, such assessment being a matter within the institutional competence of the arbitrators. The defect of reasoning under Article 829 n. 5 of the Code of Civil Procedure arises exclusively where the reasoning is entirely absent or so deficient as not to allow an understanding of the reasoning process of the arbitrators and the identification of the ratio decidendi.
The defect of inconsistency of the award under Article 829(1) n. 11 of the Code of Civil Procedure exists when the different parts of the operative part of the award are contradictory to one another or there is a contradiction between the reasoning and the operative part of the award.
The arbitral award is affected by the defect of failure to adjudicate under Article 829(1) n. 12 of the Code of Civil Procedure where the arbitral tribunal fails to decide on a claim expressly formulated by the party, including the claim for damages in excess of statutory interest.
The violation of the adversarial principle under Article 829(1) n. 9 of the Code of Civil Procedure arises where there has been a violation of the parties' right of defence in the arbitral proceedings.
Where the arbitral tribunal orders the set-off of the costs of the proceedings pursuant to Article 92 of the Code of Civil Procedure, it must also rule on the costs of the court-appointed expert examination carried out in the proceedings, recognising in favour of the party that advanced them in full the right of recourse in the amount of fifty per cent against the other party.