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NumericalGodeaux :: getRelationsAndNormalForm

getRelationsAndNormalForm -- compute a minimal set of the relations and a normal form for d1' and d2

Synopsis

Description

The procedure uses first a 6x8 submatrix of d2 depending only on the y-variables to normalize the o-matrix in d2. Then we compute the product d1’d2 whose entries define all relations between the known and unknown variables of the set-up. After evaluating the relations which are linear in the unknown variables we see that the entries of the matrix e and p depend only on the entries of the a-matrix. Furthermore, the entries of the n-matrix depend only on the a-, c- and o-variables. Updating the original matrices, we obtain normal forms for d1 and d2 whose entries depend only on the a-,c-, o- and y-variables. The remaining linear relations are stored in the matrix relLin, whereas the quadratic relations are saved in the matrix relPfaf. These relations are usually Pfaffians of rank 5 or 6.

i1 : kk = ZZ/197;
i2 : s = "1111";
i3 : (A,B,subs0) = globalVariables(kk,s);
i4 : SR = ring(A);
i5 : D = complexModuloRegularSequence(SR,s);
i6 : (d1',d2) = setupGeneralMatrices(D,A,B);
i7 : (relLin,relPfaf,d1'nor,d2nor) = getRelationsAndNormalForm(d1',d2,subs0);
i8 : betti relLin, betti relPfaf

             0  1         0 1
o8 = (total: 1 42, total: 1 4)
          0: 1  .      0: 1 .
          1: .  .      1: . .
          2: .  .      2: . .
          3: . 12      3: . 4
          4: .  .
          5: . 30

o8 : Sequence
i9 : transpose relPfaf

o9 = {-4} | a_(3,2,3)a_(3,1,3)-a_(2,2,3)a_(2,1,2)+a_(1,1,3)a_(1,1,2)  |
     {-4} | -a_(3,2,3)a_(3,0,3)+a_(2,2,3)a_(2,0,2)+a_(0,0,3)a_(0,0,2) |
     {-4} | -a_(3,1,3)a_(3,0,3)-a_(1,1,3)a_(1,0,1)+a_(0,0,3)a_(0,0,1) |
     {-4} | a_(2,1,2)a_(2,0,2)-a_(1,1,2)a_(1,0,1)+a_(0,0,2)a_(0,0,1)  |

                                                                                                                                                                                                                                                                                                                                                                4                                                                                                                                                                                                                                                                                                                                                          1
o9 : Matrix (kk[a     , a     , a     , a     , a     , a     , a     , a     , a     , a     , a     , a     , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , o     , o     , o     , o     , o     , o     , o     , o     , o     , o     , o     , o     , x , x , y , y , y , y ])  <--- (kk[a     , a     , a     , a     , a     , a     , a     , a     , a     , a     , a     , a     , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , c   , o     , o     , o     , o     , o     , o     , o     , o     , o     , o     , o     , o     , x , x , y , y , y , y ])
                 3,2,3   3,1,3   3,0,3   2,2,3   2,1,2   2,0,2   1,1,3   1,1,2   1,0,1   0,0,3   0,0,2   0,0,1   0,0   0,2   0,4   0,6   0,7   1,1   1,3   1,4   1,5   1,6   2,1   2,2   2,3   2,5   2,7   3,0   3,1   3,3   3,5   3,7   1,0,0   2,0,1   2,1,2   3,0,0   3,1,0   4,0,1   4,2,1   4,3,3   5,1,2   5,2,2   5,3,3   5,4,3   0   1   0   1   2   3              3,2,3   3,1,3   3,0,3   2,2,3   2,1,2   2,0,2   1,1,3   1,1,2   1,0,1   0,0,3   0,0,2   0,0,1   0,0   0,2   0,4   0,6   0,7   1,1   1,3   1,4   1,5   1,6   2,1   2,2   2,3   2,5   2,7   3,0   3,1   3,3   3,5   3,7   1,0,0   2,0,1   2,1,2   3,0,0   3,1,0   4,0,1   4,2,1   4,3,3   5,1,2   5,2,2   5,3,3   5,4,3   0   1   0   1   2   3

Ways to use getRelationsAndNormalForm :