Abstract
The theorem proves that any network function executed by a linear network is a bilinear function of any bilateral or unilateral element immittance embedded in the network. This result is then used to derive some difference-quotient theorems expressing the exact sensitivity of the network.Some theorems previously published by Parker, Peskin and Chirlian are shown to be corollaries of the above theorems, and the classical insertion theorem is shown in turn to be a corollary of Parker, Peskin and Chirlian's bilinear theorem.