Challenge of an award under Article 829 of the Code of Civil Procedure is admitted solely to assert errors in law (errores in iudicando) and procedural errors (errores in procedendo), within the boundaries dictated by the provision, and having the character of a judgment of limited scrutiny cannot admit re-examination on the merits by the challenge court, permitting exclusively rescinding judgment (iudicium rescindens).
Internal contradiction between different parts of the award's reasoning is not expressly provided among the defects that entail nullity of the award and may assume relevance as a defect only when it renders absolutely impossible the reconstruction of the logical and legal reasoning supporting the decision, by reason of total absence of reasoning.
Only in cases of rescinding judgment concluded with ascertainment of nullity of the award does Article 830 of the Code of Civil Procedure permit re-examination on the merits of the arbitral pronouncement, which forms the subject of any subsequent rescissory judgment (iudicium rescissorium).
Challenge of an award is not available in connection with mere assertion of investigative and reasoning lacunae that could evidence non-observance of law only upon verification of omitted or inadequate examination of decisive circumstances.
The admissibility of re-examination on the merits of an award is subordinated to preliminary resolution of the question of violation of law opposable by challenge on grounds of law and only on condition that error in the legal principle applied is explicitly alleged in respect of elements ascertained by the arbitrators.