In the interpretation of an arbitration clause aimed at determining whether the arbitration is institutional or contractual, the conferment upon arbitrators of the power to decide as amiable compositeurs is not a decisive element, since parties may also authorise institutional arbitrators to decide according to equity; what is relevant, in the sense of the institutional nature of the arbitration, is the use of expressions proper to jurisdictional proceedings, such as the referral to arbitrators of the resolution of all disputes that may arise from a given contract.
The provision in the arbitration clause of the figure of the arbitrator as amiable compositeur does not automatically imply that, once the conciliation attempt has failed, the decision must be rendered according to equity rather than according to law, such interpretation constituting a distortion not supported by further textual or behavioural elements of the parties.
The challenge to the nullity of the arbitral award for lack of reasoning is unfounded when the logical-legal reasoning of the decision is clearly reconstructible, the criticism resolving into a contestation of the merits of the evaluation of facts and evidence carried out by the arbitrator, which is beyond review in nullity proceedings.