Abstract:
A number of important theorems have been developed regarding the qualitative properties that input-output and related economic models must possess in order to be viable. That a number of apparently different notions of viability turn out to be equivalent, is one of the more important results. These thoerems , normally expressed in the vernacular of the mathematician, have enjoyed only limited recognition, however, despite their proven usefulness and the every increasing interest in such models. The strategy o this paper will be to exploit the purely geometrical nature of one condition for viability in orde to expose the quivalence of seven other important conditions. It is hoped that this relatively simple exposition will not only tie the main mathematical results together but will also bring these results within the reach of a wider audience.
