In this paper, we prove that in a simple model of income determination, when taking into account linear functions, the change rate for the gross domestic product (GDP) is equal to the quotient of the increase in investment and the sum of exogenous consumption plus the initial investment. This...

This article describes the immigration of the Spanish Regional Community of Valencia. The population of Spain has jumped to 44 million people, thanks to almost 4 million new immigrants. Much of the present migration is to cities. Foreigners make up 19 percent of the population (and 28 percent of...