A judgment by which an ordinary court affirms or denies its own jurisdiction in connection with the existence of an arbitration agreement determines exclusively a question of jurisdiction and is therefore challengeable only through the regolamento di competenza procedure under arts. 42, 43 and 47 of the Code of Civil Procedure, and not by way of ordinary appeal; where that procedure is not timely invoked, the ruling on jurisdiction becomes final and binding also upon the arbitral tribunal. This applies a fortiori where the court of first instance has not adjudicated the merits, having confined itself to declaring its own lack of jurisdiction and revoking the payment order in opposition.
A jurisdiction clause (clausola compromissoria) contained in a contract binds exclusively the parties who signed it and cannot be relied upon against third parties who are strangers to the contract, even if separate contractual relationships exist between them and the contracting parties.