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getOneParameterFamily -- Compute a one parameter smoothing family

Description

We compute a one-parameter smoothing family which uses the same terms as the matrix 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);

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 : J1=getOneParameterFamily(J,base,family,4)
   #pos = 2, #posa = 2

              3             16      17                 2 13      19   4
o5 = ideal (x  - x x  + x z   + x z  , x x  - x x  + x z   + x z  , x  - x x
              1    0 3    1       0      1 5    0 6    0       1      0    1 6
        13    2 14   2      2        14      16    2 17        18
 + x x z   + x z  , x x  - x x  - x z   + x z   + x z   + x x z   +
    0 1       0      1 3    0 5    5       3       1       0 1
  2 19   2    2      3 13      14    2 18         19      27    34
 x z  , x  - x x  + x z   - x z   + x z   + 2x x z   + x z   - z  , x x
  0      3    0 6    0       6       1        0 1       0            3 5
    2        2 13      16      17      19      29    36   3 2
 - x x  + x x z   - x z   - x z   + x z   + x z   - z  , x x  - x x  +
    1 6    0 1       6       5       3       0            0 1    3 6
      13      2 14    3 16      17   3      2    2   16    3 17      18
 x x z   + x x z   + x z   + x z  , x x  - x  + x x z   + x z   + x z   -
  0 3       0 1       0       6      0 3    5    0 1       0       6
    31    38   2                   13      2 16    2   17    3 18
 x z   + z  , x x x  - x x  + x x z   + x x z   + x x z   + x z   +
  0            0 1 3    5 6    0 5       0 1       0 1       0
    19   3      2         13        14    3 19    2 26      33
 x z  , x x  - x  + 2x x z   + x x z   + x z   - x z   + x z  )
  6      0 5    6     0 6       0 5       0       0       0

o5 : Ideal of R
i6 : J_*/size

o6 = {4, 5, 5, 7, 9, 9, 8, 7, 9, 9}

o6 : List
i7 : J1_*/size

o7 = {4, 4, 4, 7, 8, 8, 6, 7, 7, 7}

o7 : List

See also

Ways to use getOneParameterFamily:

  • getOneParameterFamily(Ideal,Ideal,Matrix,ZZ)

For the programmer

The object getOneParameterFamily is a method function with options.


The source of this document is in WeierstrassSemigroups.m2:2274:0.