Valore Attuale e Montante nei progetti puri

In order to ensure the uniqueness of the Internal Rate of Return (I.R.R.) of a given project, two different proceedings can be found in the economic-financial literature: one based on the uniqueness of the I.R.R., later performed by the concept of purity, and another referring to the so-called Truncation Theorem. The aim of this paper is to explain the connections between the purity of the I.R.R. of a given project and the truncatability of the project itself. We will clarify a very important relation between purity and truncatability: if a given investment project as a "pure" I.R.R. i0, then its Presen Value is maximum compared with the Present Values of each of its shorter lives, when the rate of interest i belongs to an interval of the type ]-1;umax[, whith i0≤imax, and, as a main consequence, we will show that purity is necessary and sufficient for truncability. © 1989 Springer-Verlag.