Top
Back: primdecGTZE
Forward: primdecSYE
FastBack:
FastForward:
Up: primdec_lib
Top: Singular Manual
Contents: Table of Contents
Index: Index
About: About this document

D.4.21.4 primdecSY

Procedure from library primdec.lib (see primdec_lib).

Usage:
primdecSY(I, c); I ideal, c int (optional)

Return:
a list pr of primary ideals and their associated primes for proper ideal I, otherwise pr[1] is list( ideal(1),ideal(1) )'
 
   pr[i][1]   the i-th primary component,
   pr[i][2]   the i-th prime component.

Note:
Algorithm of Shimoyama/Yokoyama.
 
   if c=0,  the given ordering of the variables is used,
   if c=1,  minAssChar tries to use an optimal ordering (default),
   if c=2,  minAssGTZ is used,
   if c=3,  minAssGTZ and facstd are used.
For local orderings, the result is considered in the localization of the polynomial ring, not in the power series ring.
For local and mixed orderings, the decomposition in the corresponding global ring is returned if the string 'global' is specified as third argument

Example:
 
LIB "primdec.lib";
ring  r = 0,(x,y,z),lp;
poly  p = z2+1;
poly  q = z3+2;
ideal i = p*q^2,y-z2;
list pr = primdecSY(i);
pr;
==> [1]:
==>    [1]:
==>       _[1]=z2+1
==>       _[2]=y-z2
==>    [2]:
==>       _[1]=z2+1
==>       _[2]=y+1
==> [2]:
==>    [1]:
==>       _[1]=z6+4z3+4
==>       _[2]=y-z2
==>    [2]:
==>       _[1]=z3+2
==>       _[2]=y-z2


Top Back: primdecGTZE Forward: primdecSYE FastBack: FastForward: Up: primdec_lib Top: Singular Manual Contents: Table of Contents Index: Index About: About this document
            User manual for Singular version 4-0-3, 2016, generated by texi2html.