Networks, multipoles and multiports

Starting point is the definition of networks as ordered pairs of a skeleton and a constitutive relation. The skeleton describes the topological structure of a network. The constitutive relation describes the physical properties assigned to its branch set. The behavior of a network is defined as the set of all signal pairs obeying its constitutive relation and both Kirchhoff's laws. Multipoles are introduced as ordered pairs consisting of a network and a family of terminal classes. The terminal classes are disjoint subsets of the node set of the corresponding network. Multiports are defined as multipoles whose terminal classes contain exactly two nodes. Based on these concepts a general theory of the terminal behavior of multipoles is developed.