Art. 819-ter cod. proc. civ., introduced by art. 22 of d.lgs. 40/2006, insofar as it prescribes that the judgment by which the court affirms or denies its own jurisdiction in relation to an arbitration agreement is challengeable pursuant to arts. 42 and 43 cod. proc. civ. by means of a mandatory application for the determination of jurisdiction, applies, in accordance with the principle tempus regit actum, to all decisions rendered after its entry into force (2 March 2006), irrespective of the date on which the proceedings were commenced.