# Statement

# Proof

If we have a linear programme given by $A$, $b$, and $c$, then from the weak duality theorem we have

$$ c^Tx \leq b^Ty$$

for all feasible $x$ in the original linear programme and $y$ in the dual linear programme . Therefore, if the original linear programme is unbounded , then no feasible $y$ exists, making the dual linear programme infeasible .