Opened 8 years ago

Closed 8 years ago

# another example for incomplete primdecSY() decomposition

Reported by: Owned by: kroeker@… decker minor 4-1-0 and higher dontKnow 4-0-1 primdecSY incomplete decomposition

### Description

```system("random",1947043918);
LIB("primdec.lib");
LIB("ehv.lib");
ring rng = (13931,vv),(xx,yy,zz,ww),dp;
minpoly = (vv^2-13);
ideal I = 5531*xx*zz^2+(1016*vv),(169*vv)*yy^2*ww+2197*xx,-3044*xx^2*ww+1362;
list L1 = primdecGTZ(I);
list L2 = primdecSY(I);

L1;
L2;

ASSUME(0, testPrimary( L1 , I ) );
ASSUME(0, testPrimary( L2 , I ) );

primDecsAreEquivalent(L1, L2);
```

output

```. L1;
[1]:
[1]:
_[1]=yy*ww-3136*zz
_[2]=zz^2+(723*vv)*xx*ww
_[3]=yy*zz+(-3425*vv)*xx
_[4]=xx^2*ww+2956
_[5]=xx^2*zz+3537*yy
_[6]=xx^3+(-1299*vv)*yy^2
[2]:
_[1]=yy*ww-3136*zz
_[2]=zz^2+(723*vv)*xx*ww
_[3]=yy*zz+(-3425*vv)*xx
_[4]=xx^2*ww+2956
_[5]=xx^2*zz+3537*yy
_[6]=xx^3+(-1299*vv)*yy^2
[2]:
[1]:
_[1]=yy*ww+3136*zz
_[2]=zz^2+(723*vv)*xx*ww
_[3]=yy*zz+(3425*vv)*xx
_[4]=xx^2*ww+2956
_[5]=xx^2*zz-3537*yy
_[6]=xx^3+(-1299*vv)*yy^2
[2]:
_[1]=yy*ww+3136*zz
_[2]=zz^2+(723*vv)*xx*ww
_[3]=yy*zz+(3425*vv)*xx
_[4]=xx^2*ww+2956
_[5]=xx^2*zz-3537*yy
_[6]=xx^3+(-1299*vv)*yy^2
> L2;
[1]:
[1]:
_[1]=zz^2+(723*vv)*xx*ww
_[2]=yy^2*ww+(vv)*xx
_[3]=xx^2*ww+2956
_[4]=xx^3+(-1299*vv)*yy^2
[2]:
_[1]=zz^2+(723*vv)*xx*ww
_[2]=yy^2*ww+(vv)*xx
_[3]=xx^2*ww+2956
_[4]=xx^3+(-1299*vv)*yy^2
>
. ASSUME(0, testPrimary( L1 , I ) );
> ASSUME(0, testPrimary( L2 , I ) );
>
. primDecsAreEquivalent(L1, L2);
0

```

`primdecSY( std(I) ); ` succeeds

### comment:1 Changed 8 years ago by Oleksandr

Owner: changed from somebody to decker

### comment:2 Changed 8 years ago by hannes

Resolution: → fixed new → closed
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