Singular

D.6.11.15 stripHNE

Usage:

stripHNE(L); L list

Assume:

L is the output of develop(f), or of extdevelop(develop(f),n), or (one entry of) the list hne in the ring created by hnexpansion(f[,"ess"]).

Return:

list in the same format as L, but all polynomials L[4], resp. L[i][4], are set to zero.

Note:

The purpose of this procedure is to remove huge amounts of data no longer needed. It is useful, if one or more of the polynomials in L consume much memory. It is still possible to compute invariants, parametrizations etc. with the stripped HNE(s), but it is not possible to use extdevelop with them.

LIB "hnoether.lib";
ring r=0,(x,y),dp;
list Hne=develop(x2+y3+y4);
Hne;
==> [1]:
==>    _[1,1]=0
==>    _[1,2]=x
==>    _[2,1]=0
==>    _[2,2]=-1
==> [2]:
==>    1,-1
==> [3]:
==>    1
==> [4]:
==>    x4-2x2y+y2+y
==> [5]:
==>    1
stripHNE(Hne);
==> [1]:
==>    _[1,1]=0
==>    _[1,2]=x
==>    _[2,1]=0
==>    _[2,2]=-1
==> [2]:
==>    1,-1
==> [3]:
==>    1
==> [4]:
==>    0
==> [5]:
==>    1