Nationality — Individual investor — ICSID Convention, Article 25(1) and (2)(b) — Laws applicable to determining nationality — Provision for determining nationality under Bilateral Investment Treaty — Application of domestic laws of State whose nationality investor claiming — Competence of Tribunal to apply domestic laws when deciding issues of jurisdiction

Municipal law — Loss of nationality through operation of Italian domestic law — Applicable domestic laws for reacquisition of Italian nationality — Whether Claimant complying with applicable domestic laws — Interpretation of “residence” in applicable domestic laws — Whether Claimant maintaining actual habitual residence in accordance with applicable domestic laws — Whether Claimant satisfying burden of proof

Nationality — Evidence — Whether Tribunal bound by rules of evidence in Italian civil procedure — Whether official documents of State authorities conclusive proof of nationality — ICSID Arbitration Rule 34(1) — Tribunal’s competence to judge admissibility and probative value of evidence