“…Using the definition of A S , we know that r ≥ s. We have to consider several cases: Case 1: a r,j = c r,j and a s,l = c s,l . Using the construction of C and the definition of So, we get (2). Suppose that r = s < m. Since a r,j + a r−1,j ≥ a r,l + a r−1,l > p and the fact that if c r−1,j = a r−1,j = p then c r−1,l = a r−1,l = p, we conclude that c r,j + c r−1,j ≥ c r,l + c r−1,l and c i,j = c i,l = p, for i = 1, .…”