Relationship of international law and municipal law — Recognition and enforcement of foreign laws — Expropriation legislation allegedly contrary to international law — Whether entitled to recognition in Italian courts — Public policy — Act of State doctrine — Whether Italian courts entitled to question compatibility of expropriation legislation with international law — “Pursuit actions” — Ownership of oil extracted from concession area after expropriation of concession — Ownership governed by lex rei sitae — Property in oil only acquired on extraction — Whether extraction pursuant to allegedly unlawful expropriation confers title

Expropriation — Compensation — Lack of effective compensation — Discrimination — Whether expropriation unlawful — Effect of unlawful expropriation — Whether a nullity — Whether ownership of expropriated property affected — Ownership of oil extracted from concession area after expropriation of concession — The law of Italy