Singular Book 1.8.7 -- solving equations

i1 : A = QQ[x,y,z,MonomialOrder=>Lex];

i2 : I = ideal(x^2+y+z-1, x+y^2+z-1, x+y+z^2-1);

o2 : Ideal of A

i3 : transpose gens gb I

o3 = {-6} | z6-4z4+4z3-z2 |
     {-4} | 2yz2+z4-z2    |
     {-2} | y2-y-z2+z     |
     {-2} | x+y+z2-1      |

             4       1
o3 : Matrix A  <--- A