Abstract
During a communication act, the source sends a message to one or more addressees, T, using a channel and a code, D, so that the message will not be received by certain members of a population, X. It follows that a communication act can be represented through the system (T, D, X), where T, D, and X are parts of a population, T is not empty, and T and X are disjoint sets. Using such a model, we can approach some issues of the communication sciences from a set-theoretic perspective. In this study, the main types and effectiveness conditions of the communication acts are investigated.