! Benders example problem from: Georgios Patsakis (UC Berkeley, Amazon) and Richard L.-Y. Chen (Amazon).

c1: [1 6 5 7]
c2: [9 3 0 2 3]
b: [-3 -4 1 4 5]
A1: [0 -2  3  2
   -5  0 -3  1
   1  0  4 -2
   0 -3  4 -1
   -5 -4  3  0]
A2: [3  4  2  0 -5
    0  2  3 -2  1
    2  0  1 -3 -5
    -5  3 -2 -3  0
    -2  3 -1  2 -4]