that the regulation shall not extend to "the liability of the State for acts and omissions in the exercise of State authority (acta iure imperii)." There are some exceptions limiting the scope of this. Where the principal matter of a dispute is one of family law, bankruptcy or insolvency, social security, or relates to arbitration, the case is not subject to the rules. The regulation aims at jurisdiction, i.e., determining which court or courts will have the ability to take the case. That does not mean that the applicable law will be the law of the court. It is possible and frequent to have a national court applying foreign law. In general, it is the domicile of the defendant that determines which of the courts have jurisdiction in a given case. The regime prescribes that, subject to specific rules set out in the various instruments, a person (legal or natural) may only be sued in the member state in which he or she has its habitual residence or domicile. This is determined by the law of the court hearing the case, so that a person can be domiciled in more than one state simultaneously. However, "domicile" does not have the same meaning as that given to it by common law. Article 4 also allows a person domiciled in any member state to take advantage of another member state's exorbitant bases of jurisdiction on the same basis as a national of that state. This is useful in cases where a member state, such as France, allows its nationals to sue anyone in their courts, so that someone domiciled in a member state like Finland may sue someone domiciled in a non-member state like Canada, in the courts of a third party member state, like France, where the defendant may have assets. The Brussels Convention and the Brussels I Regulation are both subject to the jurisdiction of the European Court of Justice (ECJ, now known as CJEU) on questions of interpretation. The Lugano Convention does not require non-EU states to refer questions of interpretation to the ECJ, but has a protocol regarding "uniform interpretation" of the convention, requiring courts "pay due account to the principles laid down by any relevant decision" and allowing for the exchange of relevant judgments. Nevertheless, various divergences have arisen between member states in the interpretation of the Lugano Convention. The Brussels Regime generally allows jurisdiction clauses in