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D.4.18.4 modDec

Procedure from library mprimdec.lib (see mprimdec_lib).

Usage:
modDec (N[, i]); module N, int i

Return:
list l
a minimal primary decomposition of N
computed by an generalized version of the algorithm of Shimoyama/Yokoyama,
if i=1 is given, the factorizing Groebner basis algorithm is used internally.

Example:
 
LIB "mprimdec.lib";
ring r=0,(x,y,z),dp;
module N=x*gen(1)+ y*gen(2),
x*gen(1)-x2*gen(2);
list l=modDec(N);
l;
==> [1]:
==>    [1]:
==>       _[1]=x*gen(1)+y*gen(2)
==>       _[2]=x*gen(2)-gen(1)
==>    [2]:
==>       _[1]=x2+y
==> [2]:
==>    [1]:
==>       _[1]=gen(2)
==>       _[2]=x*gen(1)
==>    [2]:
==>       _[1]=x