$2.$ Consider the network in Figure $2.$ It includes two O$-$D pairs

$(1->4$

and

$2->4)$

and five links. $($The link numbers are shown on the respective link.$)$ Devise a numbering system for the paths and identify the values of all the indicator variables. Write the link$-$path incidence matrix for this network. Use this matrix to get

x

$3$

$$