With regard to institutional arbitration, for the purposes of establishing the defect of failure to rule pursuant to Article 829, paragraph 1, No. 12, of the Code of Civil Procedure, it is not sufficient that there be a lack of an express determination on a claim or defence raised by a party; rather, it is necessary that the provision indispensable for the resolution of the concrete case be completely omitted, it being possible to find an implicit dismissal where the claim not expressly examined is incompatible with the logical-legal framework of the award, in the sense that the claim or defence is superseded and overridden by the resolution of another issue whose examination presupposes, as a necessary logical-legal antecedent, their irrelevance or lack of merit.
The contradiction in an arbitral award relevant for the purposes of challenge for nullity pursuant to Article 829, paragraph 1, No. 11, of the Code of Civil Procedure does not correspond to the defect of contradiction in the reasoning, but must be understood in the sense that the conflict must emerge between the different components of the operative part, or between the reasoning and the operative part, whereas internal contradiction between different parts of the reasoning is not relevant as a defect in itself, but only when it prevents the reconstruction of the logical and legal reasoning underlying the decision due to the total absence of reasoning referable to its functional model.
With regard to arbitration, the obligation to provide a summary statement of the reasons for the decision imposed on arbitrators by Article 823, paragraph 2, No. 5, of the Code of Civil Procedure, the non-fulfilment of which gives rise to the possibility of challenging the award pursuant to Article 829, paragraph 1, No. 5, of the Code of Civil Procedure, may be considered not satisfied only when the reasoning is entirely lacking or is so deficient as not to allow the logical reasoning that determined the arbitral decision to be understood, or contains irreconcilable contradictions such as to render the ratio of the decision incomprehensible.
In proceedings for challenge for nullity of an arbitral award, having the nature of proceedings subject to restricted grounds of challenge that may be brought within the limits established by Article 829 of the Code of Civil Procedure, the rule of specificity in the formulation of grounds applies, which is satisfied when the challenger specifies the parts of the award considered defective, the reasons why the arbitrator would have incurred the defect of nullity and the reference of each ground to one or more of the specific circumstances provided for by the provision.