[ A b] gkz [eq v] [ A ] gkz [eq v] [ ] gkz [eq v] array of array of integer A; array of integer b; eq is the GKZ system defined by the matrix A and the parameter b. v is the list of variables. Default values of A and b are in gkz.A and gkz.b For details, see Functional analysis and its applications, 23, 1989, 94--106. Grobner deformations of hypergeometric differential equations, Springer, 1999 Example 1: [ [[1 1 1 1] [0 1 3 4]] [1 2]] gkz rrank :: Example 2: [ [[1 1 1 1] [0 1 3 4]] [0 0]] gkz rrank ::