Relatively inertial delays

The delays are the mathematical models of the delay circuits. Delay theory is the mathematical theory that considers the fundamental circuit in digital electronics be the delay circuit and modeling is made by using delays and Boolean functions. The most detailed level of modeling is considered, starting from the delays that occur in gates and wires. Relative inertia is the property of the states of having their speed of variation limited by the persistency of the input and the relatively inertial delays are these delays the states of which are relatively inertial. Even if the concept has close connections with the published literature, it has a severe shortcoming: the serial connection of two relatively inertial delays is not always a relatively inertial delay. Some major properties of these delays are presented as well as the relation with absolute inertia and with zenoness.