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getParameterFamily -- Compute the parametric family which uses the same terms as J

Description

We compute the flat family of ideals which uses the same terms as J. The ideal base contains the flatness relations for the coefficients of the family.

i1 : R=QQ[x_0..x_1, x_3, x_5..x_6, z, Degrees => {7..8, 17, 19..20, 1}]

o1 = R

o1 : PolynomialRing
i2 : J=ideal(x_1^3-x_0*x_3+x_1*z^16+x_0*z^17,x_1*x_5-x_0*x_6+x_0^2*z^13+x_1*z^19-x_0*z^20,x_0^4-x_1*x_6+x_0*x_1*z^13
   +x_0^2*z^14-x_1*z^20,x_1^2*x_3-x_0^2*x_5-x_5*z^14+x_3*z^16+x_1^2*z^17+x_0*x_1*z^18+x_0^2*z^19,x_3^2-x_0^2*x_6
   +x_0^3*z^13-x_6*z^14+x_1^2*z^18+2*x_0*x_1*z^19-x_0^2*z^20+x_0*z^27-2*z^34,x_3*x_5-x_1^2*x_6+x_0*x_1^2*z^13-x_
   6*z^16-x_5*z^17+x_3*z^19-x_1^2*z^20+x_0*z^29-2*z^36,x_0^3*x_1^2-x_3*x_6+x_0*x_3*z^13+x_0*x_1^2*z^14+x_0^3*z^
   16+x_6*z^17-x_3*z^20+z^37,x_0^3*x_3-x_5^2+x_0^2*x_1*z^16+x_0^3*z^17+x_6*z^18-x_0*z^31+2*z^38,x_0^2*x_1*x_3-x_
   5*x_6+x_0*x_5*z^13+x_0*x_1^2*z^16+x_0^2*x_1*z^17+x_0^3*z^18+x_6*z^19-x_5*z^20+z^39,x_0^3*x_5-x_6^2+2*x_0*x_6*
   z^13+x_0*x_5*z^14+x_0^3*z^19-2*x_6*z^20-x_0^2*z^26+3*x_0*z^33-z^40)

             3             16      17                 2 13      19      20
o2 = ideal (x  - x x  + x z   + x z  , x x  - x x  + x z   + x z   - x z  ,
             1    0 3    1       0      1 5    0 6    0       1       0
  4               13    2 14      20   2      2        14      16    2 17
 x  - x x  + x x z   + x z   - x z  , x x  - x x  - x z   + x z   + x z
  0    1 6    0 1       0       1      1 3    0 5    5       3       1
        18    2 19   2    2      3 13      14    2 18         19    2 20
 + x x z   + x z  , x  - x x  + x z   - x z   + x z   + 2x x z   - x z
    0 1       0      3    0 6    0       6       1        0 1       0
      27     34          2        2 13      16      17      19    2 20
 + x z   - 2z  , x x  - x x  + x x z   - x z   - x z   + x z   - x z   +
    0             3 5    1 6    0 1       6       5       3       1
    29     36   3 2               13      2 14    3 16      17      20
 x z   - 2z  , x x  - x x  + x x z   + x x z   + x z   + x z   - x z   +
  0             0 1    3 6    0 3       0 1       0       6       3
  37   3      2    2   16    3 17      18      31     38   2
 z  , x x  - x  + x x z   + x z   + x z   - x z   + 2z  , x x x  - x x  +
       0 3    5    0 1       0       6       0             0 1 3    5 6
      13      2 16    2   17    3 18      19      20    39   3      2
 x x z   + x x z   + x x z   + x z   + x z   - x z   + z  , x x  - x  +
  0 5       0 1       0 1       0       6       5            0 5    6
       13        14    3 19       20    2 26       33    40
 2x x z   + x x z   + x z   - 2x z   - x z   + 3x z   - z  )
   0 6       0 5       0        6       0        0

o2 : Ideal of R
i3 : L=flatten drop(degrees R,-1)

o3 = {7, 8, 17, 19, 20}

o3 : List
i4 : (base,family)=getParameterFamily J;
i5 : numgens base

o5 = 4
i6 : cbase=decompose base


o6 = {ideal (a      , a      , a      ), ideal (a      a       - a      a
             {1, 3}   {2, 3}   {0, 2}           {0, 2} {2, 3}    {0, 1} {1,
                                       2
   , a      a       - a      a      , a       - a      a      , a
 3}   {3, 4} {2, 3}    {1, 2} {1, 3}   {0, 2}    {1, 2} {1, 3}   {0,
   a       - a      a      , a      a       - a      a      )}
 1} {0, 2}    {1, 2} {2, 3}   {3, 4} {0, 1}    {1, 2} {0, 2}

o6 : List
i7 : J_0

      3             16      17
o7 = x  - x x  + x z   + x z
      1    0 3    1       0

o7 : R
i8 : family_(0,0)

     3
o8 = x  - x x  + x a       + x a
     1    0 3    0 {0, 1}    1 {0, 2}

o8 : QQ[x ..x , x , x ..x , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a       , a      , a      , a      , a      , a      , a       , a       , a      , a      , a      , a      , a       , a       , a      , a      , a      , a       , a       , a       , a       , a      , a      , a      ]
        0   1   3   5   6   {9, 0}   {8, 0}   {7, 0}   {6, 0}   {5, 0}   {4, 0}   {9, 1}   {7, 1}   {5, 1}   {4, 1}   {9, 3}   {9, 8}   {8, 7}   {6, 6}   {5, 5}   {4, 3}   {2, 2}   {1, 1}   {9, 9}   {8, 8}   {5, 6}   {4, 4}   {3, 3}   {1, 2}   {8, 9}   {7, 8}   {4, 5}   {3, 4}   {8, 10}   {7, 9}   {6, 8}   {5, 7}   {3, 5}   {0, 1}   {8, 11}   {7, 10}   {6, 9}   {5, 8}   {3, 6}   {0, 2}   {9, 14}   {6, 11}   {4, 8}   {3, 7}   {2, 3}   {9, 15}   {8, 14}   {6, 12}   {5, 11}   {4, 9}   {2, 4}   {1, 3}
i9 : J_*/size

o9 = {4, 5, 5, 7, 9, 9, 8, 7, 9, 9}

o9 : List
i10 : (ideal family)_*/size

o10 = {4, 5, 5, 7, 10, 10, 8, 8, 9, 10}

o10 : List
i11 : J_4

      2    2      3 13      14    2 18         19    2 20      27     34
o11 = x  - x x  + x z   - x z   + x z   + 2x x z   - x z   + x z   - 2z
      3    0 6    0       6       1        0 1       0       0

o11 : R
i12 : family_(0,4)

      2    2      2                          2           2
o12 = x  - x x  + x a       + 2x x a       + x a       - a       - x a
      3    0 6    0 {1, 1}     0 1 {1, 2}    1 {3, 4}    {0, 1}    6 {2, 3}
                      3
  + a      a       + x a       + x a      a
     {1, 1} {2, 3}    0 {1, 3}    0 {2, 3} {1, 3}

o12 : QQ[x ..x , x , x ..x , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a      , a       , a      , a      , a      , a      , a      , a       , a       , a      , a      , a      , a      , a       , a       , a      , a      , a      , a       , a       , a       , a       , a      , a      , a      ]
         0   1   3   5   6   {9, 0}   {8, 0}   {7, 0}   {6, 0}   {5, 0}   {4, 0}   {9, 1}   {7, 1}   {5, 1}   {4, 1}   {9, 3}   {9, 8}   {8, 7}   {6, 6}   {5, 5}   {4, 3}   {2, 2}   {1, 1}   {9, 9}   {8, 8}   {5, 6}   {4, 4}   {3, 3}   {1, 2}   {8, 9}   {7, 8}   {4, 5}   {3, 4}   {8, 10}   {7, 9}   {6, 8}   {5, 7}   {3, 5}   {0, 1}   {8, 11}   {7, 10}   {6, 9}   {5, 8}   {3, 6}   {0, 2}   {9, 14}   {6, 11}   {4, 8}   {3, 7}   {2, 3}   {9, 15}   {8, 14}   {6, 12}   {5, 11}   {4, 9}   {2, 4}   {1, 3}
i13 : support family

o13 = {x , x , x , x , x , a      , a      , a      , a      , a      , a
       0   1   3   5   6   {1, 1}   {1, 2}   {3, 4}   {0, 1}   {0, 2}   {2,
    , a      }
  3}   {1, 3}

o13 : List
i14 : support family/degree

o14 = {{7}, {8}, {17}, {19}, {20}, {20}, {19}, {18}, {17}, {16}, {14}, {13}}

o14 : List

See also

Ways to use getParameterFamily:

  • getParameterFamily(Ideal)

For the programmer

The object getParameterFamily is a method function.


The source of this document is in WeierstrassSemigroups.m2:2162:0.