An application to set aside an award gives rise to proceedings of limited review, confined to the exhaustively listed defects, and does not allow the court hearing the challenge to re-examine the merits of the arbitral decision. There is no defect of contradiction between the reasoning and the operative part where the logical path followed by the arbitrators is coherent, intelligible and extensively reasoned, with precise identification of the contractual clauses from which the conclusions were drawn. Breach of the duty to submit to the parties the issues deemed decisive, examined directly in the arbitral decision without inviting submissions, may constitute a ground for annulment of the award only in relation to issues of fact or mixed issues, and not in relation to issues of law. No nullity of the award for breach of the adversarial principle arises where, the factual framework remaining unaltered, the arbitral tribunal merely subsumed the alleged breach under one statutory head rather than another, thereby characterising the claim in law and identifying the applicable provision.