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D.6.15.15 stripHNE
Procedure from library hnoether.lib (see hnoether_lib).
- 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.
Example:
| | 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
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See also:
develop;
extdevelop;
hnexpansion.
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