This package provides routines for computation involving components of ideals and modules, including associated primes and primary decompositions.
The following simple example illustrates the use of removeLowestDimension, topComponents, radical, minimalPrimes, associatedPrimes, and primaryDecomposition.
i1 : R = ZZ/32003[a..d]; |
i2 : I = monomialCurveIdeal(R,{1,3,4}) 3 2 2 2 3 2 o2 = ideal (b*c - a*d, c - b*d , a*c - b d, b - a c) o2 : Ideal of R |
i3 : J = ideal(a^3,b^3,c^3-d^3) 3 3 3 3 o3 = ideal (a , b , c - d ) o3 : Ideal of R |
i4 : I = intersect(I,J) 4 3 3 3 4 3 3 4 6 3 2 o4 = ideal (b - a d, a*b - a c, b*c - a*c d - b*c*d + a*d , c - b*c d - ------------------------------------------------------------------------ 3 3 5 5 2 3 2 3 2 4 2 4 3 3 3 3 2 3 c d + b*d , a*c - b c d - a*c d + b d , a c - a d + b d - a c*d , ------------------------------------------------------------------------ 3 3 3 3 2 3 3 2 3 2 2 3 2 3 3 2 3 2 b c - a d , a*b c - a c*d + b c*d - a*b d , a b*c - a c d + b c d - ------------------------------------------------------------------------ 2 3 3 3 3 2 4 2 3 2 a b*d , a c - a b*d , a c - a b d) o4 : Ideal of R |
i5 : removeLowestDimension I 3 2 2 2 3 2 o5 = ideal (b*c - a*d, c - b*d , a*c - b d, b - a c) o5 : Ideal of R |
i6 : topComponents I 3 2 2 2 3 2 o6 = ideal (b*c - a*d, c - b*d , a*c - b d, b - a c) o6 : Ideal of R |
i7 : radical I 2 2 3 2 6 3 3 2 4 5 o7 = ideal (b*c - a*d, a*c - b d, b - a c, c - c d - b d + b*d ) o7 : Ideal of R |
i8 : minimalPrimes I 3 2 2 2 3 2 o8 = {ideal (b*c - a*d, c - b*d , a*c - b d, b - a c), ideal (c - d, b, ------------------------------------------------------------------------ 2 2 a), ideal (b, a, c + c*d + d )} o8 : List |
i9 : associatedPrimes I 3 2 2 2 3 2 o9 = {ideal (b*c - a*d, c - b*d , a*c - b d, b - a c), ideal (c - d, b, ------------------------------------------------------------------------ 2 2 a), ideal (b, a, c + c*d + d )} o9 : List |
i10 : primaryDecomposition I 3 2 2 2 3 2 3 o10 = {ideal (b*c - a*d, c - b*d , a*c - b d, b - a c), ideal (c - d, b , ----------------------------------------------------------------------- 3 2 2 3 3 a ), ideal (c + c*d + d , b , a )} o10 : List |
This documentation describes version 2.0 of PrimaryDecomposition.
The source code from which this documentation is derived is in the file PrimaryDecomposition.m2. The auxiliary files accompanying it are in the directory PrimaryDecomposition/.
The object PrimaryDecomposition is a package.