This paper discusses the necessary conditions for principal and agent contract in an evolutionary interactive context and how a specific technology prevails. The resulting stabiliTY condition is an Evolutionarily Stable Strategy, ESS, in the Maynard Smith tradition. When productiviTY is greater or equal to one arises a ESS in a particular technology and when productiviTY is less than one the only way to explain why a particular technology prevails is by means of a convention.
