Formulate the dual program to a critical path problem $($its primal formulation is

already given in class$),$ and show that it is also a longest path problem.LP formulation

Min $t_n-t_1,$ Its dual program is corresponding to a longest path problem.

s$.$t$.t_j-t_i{D}_{ij},AA(i,j)inA$

$t_{i}0,i=1,2,$dots,$n.$