Action to annul an arbitration award. Allegation of irregularity in the selection of the presiding arbitrator by the two arbitrators appointed by the parties pursuant to Article 13, §2º of the Brazilian Arbitration Act. No need to file the action under Article 7 of the Brazilian Arbitration Act. Rules of the arbitration center providing for the method of appointment, which were followed in the case at hand. Interpretation of Article 13, §3º of the Brazilian Arbitration Act: