Sets -- sets of a Cartesian code

i1 : F=GF(4);

i2 : R=F[x,y];

i3 : C=cartesianCode(F,{{0,1,a},{0,1,a}},{1+x+y,x*y})

o3 = EvaluationCode{cache => CacheTable{}                                                                                                                                                                                                                                               }
                                                               9
                    LinearCode => LinearCode{AmbientModule => F                                                                                                                                                                                                                        }
                                             BaseField => F
                                             cache => CacheTable{}
                                             Code => image | 1   a+1 |
                                                           | a+1 0   |
                                                           | a+1 0   |
                                                           | a   a   |
                                                           | a   a   |
                                                           | 1   0   |
                                                           | 0   0   |
                                                           | 0   0   |
                                                           | 1   1   |
                                             GeneratorMatrix => | 1   a+1 a+1 a a 1 0 0 1 |
                                                                | a+1 0   0   a a 0 0 0 1 |
                                             Generators => {{1, a + 1, a + 1, a, a, 1, 0, 0, 1}, {a + 1, 0, 0, a, a, 0, 0, 0, 1}}
                                             ParityCheckMatrix => | 1 0 0 0 0 a   0 0 a+1 |
                                                                  | 0 1 0 0 0 a+1 0 0 0   |
                                                                  | 0 0 1 0 0 a+1 0 0 0   |
                                                                  | 0 0 0 1 0 0   0 0 a   |
                                                                  | 0 0 0 0 1 0   0 0 a   |
                                                                  | 0 0 0 0 0 0   1 0 0   |
                                                                  | 0 0 0 0 0 0   0 1 0   |
                                             ParityCheckRows => {{1, 0, 0, 0, 0, a, 0, 0, a + 1}, {0, 1, 0, 0, 0, a + 1, 0, 0, 0}, {0, 0, 1, 0, 0, a + 1, 0, 0, 0}, {0, 0, 0, 1, 0, 0, 0, 0, a}, {0, 0, 0, 0, 1, 0, 0, 0, a}, {0, 0, 0, 0, 0, 0, 1, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 1, 0}}
                    Points => {{a, a}, {0, a}, {a, 0}, {a, 1}, {1, a}, {0, 0}, {1, 0}, {0, 1}, {1, 1}}
                    PolynomialSet => {x + y + 1, x*y}
                    Sets => {{0, 1, a}, {0, 1, a}}
                                              3           2         3           2
                    VanishingIdeal => ideal (x  + (a + 1)x  + a*x, y  + (a + 1)y  + a*y)

o3 : EvaluationCode

i4 : C.Sets

o4 = {{0, 1, a}, {0, 1, a}}

o4 : List