Fertility, immigration, and lifetime wages under imperfect labor substitution

This paper provides new insights into the effect of birth cohort size on cohort lifetime wages and its sensitivity to the future trajectories of immigration and fertility. The main innovation is to relax the typical assumption of perfect substitution of labor by age. The effect of imperfect substitution of labor by age is to qualify the standard result that smaller birth cohorts are likely to enjoy relatively high wages since that result depends on the size of co-worker cohorts. The positive small cohort effect on lifetime wages therefore depends on demographic patterns, which are simulated here through low and high fertility and immigration projections. The analysis applies to actual and projected cohorts for Australia and tests the sensitivity to alternative demographic parameters, and the substitution and discount parameters. The effects of imperfect substitution can amount several percentage points of lifetime wages.

Cryptobiometrics for the Generation of Cancellable Symmetric and Asymmetric Ciphers with Perfect Secrecy

Security objectives are the triad of confidentiality, integrity, and authentication, which may be extended with availability, utility, and control. In order to achieve these goals, cryptobiometrics is essential. It is desirable that a number of characteristics are further met, such as cancellation, irrevocability, unlinkability, irreversibility, variability, reliability, and biometric bit-length. To this end, we designed a cryptobiometrics system featuring the above-mentioned characteristics, in order to generate cryptographic keys and the rest of the elements of cryptographic schemes—both symmetric and asymmetric—from a biometric pattern or template, no matter the origin (i.e., face, fingerprint, voice, gait, behaviour, and so on). This system uses perfect substitution and transposition encryption, showing that there exist two systems with these features, not just one (i.e., the Vernam substitution cipher). We offer a practical application using voice biometrics by means of the Welch periodogram, in which we achieved the remarkable result of an equal error rate of (0.0631, 0.9361). Furthermore, by means of a constructed template, we were able to generate the prime value which specifies the elliptic curve describing all other data of the cryptographic scheme, including the private and public key, as well as the symmetric AES key shared between the templates of two users.

Mathematical analysis of an economic growth model with perfect-substitution technologies

The purpose of this paper is to highlight certain features of a dynamic optimisation problem in an economic growth model with environmental negative externalities that gives rise to a two-dimensional dynamical system. In particular, it is demonstrated that the dynamics of the model, which is based on a production function with perfect substitutability (perfect substitution technologies), admits a locally attracting equilibrium with a basin of attraction that may be considerably large, as it can extend up to the boundary of the system phase plane. Moreover, this model exhibits global indeterminacy because either equilibrium of the system can be selected according to agent expectation. Formulas for the calculation of the bifurcation coefficients of the system are derived, and a result on the existence of limit cycles is obtained. A numerical example is given to illustrate the results.

JULIAN, ULPIAN I NIETYPOWA POŻYCZKA. ZASTOSOWANIE ANALOGII W ROZWAŻANIACH PRAWNICZYCH

JULIAN, ULPIAN AND THE ATYPICAL LOAN: ON ANALOGY AS APPLIED IN LEGAL REASONINGSummary The paper concerns the legal controversy as to the possibility of transforming a debt that is due under a contract of mandate or any other consensual contract into a loan by means of a bare agreement (pactum). Under such an agreement the creditor would entitle his debtor to keep the equivalent of the debt – which already existed between them – as a loan. The discussion took place between Julian, the eminent jurist of the midsecond-century A.D, and Ulpian, the jurist of the first half of the third century A.D. Julian argued against the possibility of classifying the contract in question as a loan. His arguments were based on analogy, distinction, and reductio ad absurdum (D.17,1,34 pr.). Ulpian, on the other hand, defended the possibility that was ruled out by his predecessor. Interestingly enough, the latter relies on analogy as his main argument as well. His conclusion is drawn, however, from analogy with the very same situation which Julian considered distinct from the case in question (D. 12,1,15). In the article, it is argued that this diversity of opinions can be explained by the different interpretations of the characteristic of the loan as a real contract. From Julian’s standpoint, this characteristic required the loan to be the title of acquisition by the borrower of ownership of money or things that are thereby considered the object of the loan: if the money or things were acquired on any other grounds, no loan could be construed (not to mention the case where the debtor does not – materially – acquire any money at all). Ulpian, on the other hand, was concerned not as much with the material substrate of the loan as with the economical calculus: in this perspective, indeed, the agreement – which tended to replace the hitherto debt by the loan-debt of the same amount – turned out to be a perfect substitution of a double payment, which would lead to the same effect. It is important to note one of the consequences to which Ulpian’s reasoning could lead: the possibility that someone who has never obtained any money from anyone or indeed never had them, nevertheless could be considered to have borrowed them (e.g. someone obliged to pay damages is entitled by the creditor to keep the amounts due as a loan of money that he never materially obtained). In order to accept this consequence, some serious redefinition of the concept of the loan as a real contract seems necessary, to say the least. The paper argues that – when ruling out the transformation – Julian strove to avoid accepting this very consequence.

A Semi-Nonparametric Approach to the Demand for Money in Pakistan

The degree of substitutability of different monetary assets serves as a valuable source of information for Pakistan’s monetary authorities in the context of money demand analysis. Barnett’s (1980) concept of the micro-foundations of money demand has paved the way for a more comprehensive demand system analysis. Locally flexible functional forms are unable to estimate substitution elasticities at all data points, and thus, we use the asymptotically ideal model, which is a semi-nonparametric globally flexible functional form. Our data on income, price, and substitution elasticities show that there is less-than-perfect substitution among monetary assets. The results of Allan and Morishima elasticities show that the former are inherently biased toward showing monetary assets as complements, making Morishima a better choice. The study recommends that it is high time Pakistan’s monetary authorities abandoned the simple-sum aggregation method, which assumes perfect substitution among monetary assets.

Diversion et création d’échanges commerciaux dans le cadre du système canadien de préférences tarifaires

This paper explores in quantitative terms the potential effects on trade flows as a result of Canadian tariff preferences in favor of the developing countries instituted in 1974. The paper develops a model of trade creation and trade diversion due to preferences based on imperfect substitution, within each product category, between preference-granting, preference-receiving and non-preferred countries. This model depart from the usual assumption of the customs union theory that countries trade in perfect substitutes. The model is then applied to the 1978 trade date under BTN chapters 25 - 99 on a 4-digit classification. One major conclusion of the paper is that the assumption of perfect substitution tends to overstate the magnitude of trade creation and trade diversion, while the method based on less than perfect substitutability seems to offer more realistic estimates of the actual impact of trade preferences.

Supplier Substitutability and the Impacts of the 1980 U.S. Grain Embargo

The 1980 U.S. suspension of grain sales to the Soviet Union illustrates the importance of the choice of conceptual framework for empirical analysis of international trade problems. A spatial equilibrium model of wheat and coarse grains trade assumes perfect substitution among exporting nations' commoditites by importers and, thus, precludes the embargo from having a large impact. The imperfect substitutability assumption of an Armington model results in larger consequences from the embargo. For small shocks, the Armington model better captures the rigidities characteristic of international grain markets. The spatial model provides insights on adjustments to large shocks, but rigidities persist in actual markets.