Max-plus algebra possible eigenvector of interval matrices
[As,lx] = maxplusposegv(A,B,x)
Function returns an possible eigenvalue lx and matrix As that satisfies
A≤As≤B, As⊗x = lx⊗x, and A⊗x ≤ As⊗x ≤ B⊗x.
And returns As=[], ls=[] if the vector x is not possible eigenvector of interval matrices. For more detailed, see: Cechlarova, K. (2005), "Eigenvectors of Interval Matrices over Max-Plus Algebra", Discrete Applied Mathematics, vol.150, 2-15.