Arbitration award decreeing the acquisitive prescription of property by adverse possession, ordering the issuance of a letter of request for the respective registration in the property's title record. Nullity of the award and of the letter of request declared ex officio by the judiciary, on the grounds of nullity of the arbitration agreement (Article 32, I, of the Brazilian Arbitration Act). Inherent public interest in adverse possession proceedings due to the necessary inclusion of indeterminate third parties with an interest in the case, who are not covered by the arbitration agreement: