... publicliabilities. Since immigrants typically are of working age at the time of their entry into the country, they enlarge the group of net tax payers and thus reduce the inter-temporal fiscal53 In Bonin (2001), ... presented in the previous s ec tions were derived under certain assumptions regarding the projected population, the interest rate and the growth rate. In order to test for the robustness of the findings ... wecompute the size of inter-temporal public liabilities, or the so-called ’true public debt’, whichis the difference between the nominal value of public debt at the beginning of the base yearand...