setupSkewMatrices -- compute four skew-symmetric matrices whose Pfaffians are among the quadratic relations

Synopsis

• Usage:

  Ms = setupSkewMatrices(relPfaf,s)

• Inputs:

  • relPfaf, a matrix, row matrix containing the quadratic relations from the construction
  • s, a string, describing the configuration of the 4 base points of the bicanonical system
• Outputs:

  • Ms, a sequence, three or four skew-symmetric matrices of size 4 whose entries are a-variables

Description

i1 : kk = ZZ/197;

i2 : s = "22";

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 : Ms = setupSkewMatrices(relPfaf,s);