A challenge to the validity of an arbitral award pursuant to Article 829(2) of the Code of Civil Procedure, on the ground of non-observance of rules of law in adjudication (in iudicando), is admissible only if confined within the same limits as a complaint of error of law that may be raised by way of appeal to the Court of Cassation under Article 360(1)(3) of the Code of Civil Procedure. The complaint requires the express allegation that the legal rule applied was erroneous in relation to the findings of fact made by the arbitrators and cannot be brought in connection with the mere assertion of deficiencies in the investigation, in the reasoning, or in the assessment of the evidence.
The court hearing a challenge to an arbitral award pursuant to Article 829(3) of the Code of Civil Procedure may not interfere with the examination and assessment of the evidence in order to re-evaluate the merits of the arbitral decision and reach a different final conclusion, exceeding the limits of its review, which is confined to verifying the correct application of rules of law to the findings of fact made by the arbitrators.
Inconsistency as a ground of nullity of an arbitral award must arise between different parts of the operative part of the award or between the reasoning and the operative part, whereas an internal inconsistency between different parts of the reasoning may be relevant only where it renders it absolutely impossible to reconstruct the logical and legal reasoning underlying the decision owing to the total absence of reasoning referable to its functional model.
In proceedings on remand following the setting aside by the Court of Cassation of the judgment on a challenge to an arbitral award, issues on which the court hearing the challenge did not rule, having considered them absorbed, may be raised again before the court on remand, no res judicata having been formed on such issues.
The judgment of the Court of Cassation setting aside the judgment on a challenge to an arbitral award binds the court on remand not only as to the legal rule stated but also as to the logical-legal premises of the decision, the preclusions arising from the implied res judicata formed by the judgment on the appeal applying, with the consequence that the court on remand may not extend its investigation to issues which, although not examined in the appeal on points of law, constitute the very premise of the ruling.