In recent years, there has been an explosive increase in the demand for health products and services by people all around the globe, and particularly in advanced economies. Aiming to enhance longevity and also to improve quality of life, individual consumption of pharmaceutical products and services has risen exponentially since the early 1980s. This paper develops a model in which agents invest part of their resources in medical products and time in physical exercise to enhance their health status. In the first part of the paper, we study the steady state and transitional dynamics of the model with special emphasis on the effects of health decisions on aggregate outcomes. In the second part, we explore how public health policies may alter private economic decisions that promote healthier and more productive lives.

This paper analyses the pseudo almost periodicity of the impulsive neoclassical growth model. We investigate the existence, uniqueness and exponential stability of the pseudo almost periodic solution. Moreover, an example is given to illustrate the significance of the main findings.

We study production functions with capital and labor as arguments that exhibit positive, yet diminishing marginal products and constant returns to scale. We show that such functions satisfy the Inada conditions if (i) both inputs are essential and (ii) an unbounded quantity of either input leads to unbounded output. This allows for an alternative characterization of the neoclassical production function that altogether dispenses with the Inada conditions. Although this proposition generalizes to the case of n > 2 factors of production, its converse does not hold: 2n Inada conditions do not imply that each factor is essential.

This paper surveys the contributions of David Cass, Tjalling Koopmans, and Edmond Malinvaud over the decades during which modern optimal growth theory was developed. By utilizing material ranging from dissertations, drafts, and working papers through conference presentations, discussions, and published papers, we show that both Malinvaud and Cass had significant impacts on the evolution of Koopman's thought, and the development of his part of what is known as “the Cass–Koopmans model.” Based on our findings, we conclude that the modern optimal growth model should include the contributions of Malinvaud, and be retitled “the Cass–Malinvaud–Koopmans” model accordingly.

Government shares in total output are characterized by significant variation across countries. I noticed a strong negative correlation between government consumption shares and the price of government services in terms of private consumption. Motivated by this empirical observation, I developed a neoclassical growth model with added government that is capable of matching the variation in government shares very closely using only relative prices. In addition, I provide empirical evidence showing that the relative price of government consumption increases with income, which is consistent with distortions prevailing in poor countries. These two observations combined imply that government shares tend to be higher in poorer countries.