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D.5.9.5 discr
Procedure from library spcurve.lib (see spcurve_lib).
- Usage:
discr(sem,n); sem ideal, n integer
- Assume:
sem is the versal deformation of an ideal of codimension 2.
the first n variables of the ring are treated as variables all the others as parameters- Return:
ideal describing the discriminant
- Note:
This is not a powerful algorithm!
Example:
LIB "spcurve.lib"; ring r=32003,(x(1),x(2),x(3)),ds; ideal curve=x(1)*x(2),x(1)*x(3),x(2)*x(3); matrix M=isCMcod2(curve); list l=matrixT1(M,3); def sem=semiCMcod2(l[1],std(l[2])); basering; → // characteristic : 32003 → // number of vars : 6 → // block 1 : ordering ds → // : names x(1) x(2) x(3) → // block 2 : ordering dp → // : names A(1) A(2) A(3) → // block 3 : ordering C discr(sem,3); → _[1]=A(1)*A(2)*A(3) |