|
Ring Normalization - Sturmfels example
Compute the normalization of the following subvariety of
P8
( K = Z/32003
Z )
V = { wy-vz=0 , vx-uy=0 , tv-sw=0 ,
su-bv=0 , tuy-bvz=0 }
LIB "normal.lib";
ring r=32003,(b,s,t,u,v,w,x,y,z),dp;
ideal i=wy-vz,vx-uy,tv-sw,su-bv,tuy-bvz;
list NN = normal(i); // takes about 6 sec
|
==>
|
'normal' created a list of 3 ring(s).
|
NN[1];
|
==>
|
// characteristic : 32003
// number of vars : 6
// block 1 : ordering dp
//
: names T(1) T(2) T(3) T(4) T(5) T(6)
// block 2 : ordering C
|
def R1=NN[1]; | |
def R2=NN[2]; | |
def R3=NN[3]; |
setring R1; | |
setring R2; | |
setring R3; |
norid; | |
norid; | |
norid; |
| |
| |
|
==>
|
norid[1]=wy-vz
norid[2]=ty-sz
norid[3]=wx-uz
norid[4]=vx-uy
norid[5]=tx-bz
norid[6]=sx-by
norid[7]=tv-sw
norid[8]=tu-bw
norid[9]=su-bv
|
|
normap; | |
normap; | |
normap; |
|
==>
|
normap[1]=T(1)
normap[2]=T(2)
normap[3]=T(3)
normap[4]=0
normap[5]=0
normap[6]=0
normap[7]=T(4)
normap[8]=T(5)
normap[9]=T(6)
|
| |
|
==>
|
normap[1]=T(1)
normap[2]=0
normap[3]=T(2)
normap[4]=T(3)
normap[5]=0
normap[6]=T(4)
normap[7]=T(5)
normap[8]=0
normap[9]=T(6)
|
| |
|
==>
|
normap[1]=b
normap[2]=s
normap[3]=t
normap[4]=u
normap[5]=v
normap[6]=w
normap[7]=x
normap[8]=y
normap[9]=z
|
|
The normalization (ring) is:
|