Essential nodes and essential branches

In addition to the terminology above, it is useful to introduce the concept of essential nodes and essential branches.

Essential node is a node joining three or more elements.

Essential branch is a path that connects essential nodes without passing through an essential node.

In case of a circuit analysis requirement, only essential nodes and essential branches must be taken into account.

On the above circuit there are 4 essential nodes (b,c,e,g), and on the figure below the 7 essential branches of the circuit are shown: